Build a Cheap and Fast RAID 5 NAS - Page 2 - Article-Discussions

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Sub $1500 DIY SFF 1GB DDR, Dual GbE, SATA II, RAID 5, 2.0TB NAS, quiet, and low power. Just add OS.

I found these prices at various locations.

Morex Venus 668B Case - $95.00
Commell LV-673NS Pentium M Mini-ITX Mainboard - $335.00
1GB PC3200 DDR -$56.00
Intel Celeron M CPU 1.30GHZ/1M CACHE/400MHZ FSB SL7RA - $45.00
Hitachi DeskStar 7K500 500GB SATA 3.0Gb/s Serial ATA Hard Drive - 4 x $199.00
HighPoint RocketRAID 2310 PCI Express to SATA II RAID Controller - $145.99

Reply to jasonuscg

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Quote :

All of your systems look expensive to me

I have a PIII 500mhz with 128mb of ram with an Intel 6 Port SATA Raid (bought of Ebay for $86US) controller installed. I run 4 x 320Gb WD hard drives in a RAID 5 config.
...........<edit>...........

This looks very interesting. I'm about to retire a similar box (a little higher spec actually), so I could easily add a RAID card and the same as you.
I'm a bit concerned about performance though. Have you measured file read/write performance accross the LAN?

And does anyone with a similar box have a GigE interface to report performance on that? I suspect it wouldn't be great though...

Reply to dimitrik

As several previous posters have mentioned, if you are going to do pure file sharing then you cannot beat a dedicated NAS box. NAS box does what it says on the tin, its a file server.

If you are going to the expense of building a PC, you might as well its power. For example mine does,
- File + Print sharing including Anti-virus scanning
- Internet proxy server with content filtering, caching, bandwidth shaping
- Web + FTP server
- Usenet download
- VMWare with guest O/S acting as a domain controller, DHCP, DNS, etc
Plus off load most of my computing tasks to it (e.g video encoding, PAR, RAR, etc)
All these functions (aside from the DC) are free items that a NAS server cannot do. You have paid for the power and flexibility of a PC, might as well make use of them.

I have also taken a power reading for my system (total cost approx $1k),
Intel D805 Overclocked to 3.4 GHz, 2 GB RAM, intergrated GFx, Gb NIC, 3Ware 7506 RAID controller, 2nd Gb NIC, 8 x 250GB Samsung HDD, 8 x 80mm fan. Total power as startup = 325w, idle = 280, full load = 315w.

Reply to oneman

Here's my test results using the same parameters and 64k records in IOZone as your tests.
[code:1:1f2db36f59]
Write:
filesize (k) speed (MB/s)
32768 51.659
65536 54.018
131072 47.905
262144 28.789
524288 34.469
1048576 36.241

Read:
filesize (k) speed (MB/s)
32768 60.133
65536 58.101
131072 53.663
262144 48.462
524288 55.365
1048576 37.286[/code:1:1f2db36f59]

System specs on the server are:
athlonxp 2500
768 MB DDR400 (512+256)
160 PATA, 300 SATA, 320 SATA, 400 PATA
Asus A7N8X deluxe
Intel pro 1000MT nic
Slackware 10.2 with the 2.6 kernel and standard packages installed, Xserver rarely running

Aside from the nic that i bought on purpose when i got a GbE switch, and the harddrives i buy whenever i see a great deal, i had all this stuff lying around. I'm not running any kind of raid, although it is set up in a sort of virtual JBOD fashion as there are shortcuts that point to various drives on the actual linux box that appear as normal folders to connected clients. I'm not sure why the performance of the machine in the article wasn't a bit faster, and considering my results and the results others have posted, i'm extremely disappointed with the performance of off the shelf NAS solutions. Why are they SO slow?

p.s. I feel stupid, but why is my post centered instead of left-justified?

Reply to megamojo

Hello all,

I would just like to share my experiences with RAID and NAS for home use.

I recently bought an Infrant ReadyNAS NV and loaded it with 4x250GB SATA drives (2x Maxtor, 2x Seagate) and configured it to use Infrant's expandable X-RAID configuration. I have around 680GB effective capacity available.

I bought this system with the expectation that it should be easy to configure, easy to upgrade, provide good data security, and provide good transfer rates compared to my growing collection of 2.5" and 3.5" USB/FireWire Combo HDD enclosures... :wink:

Initially, I was looking at a 4-drive 3.5" HDD enclosure with a FireWire-to-RAID-5 bridge chip. (like the ones available at http://cooldrives.stores.yahoo.net )

However, the thought of having a relatively expensive (around $1,500) Quad-bay RAID-5 enclosure or a $700 Quad-bay Dual-RAID0/1 enclosure from a no-name (probably some Taiwanese OEM company) manufacturer shipped all the way to the Philippines, then hoping that I don't encounter any compatibility issues with my locally purchased hard drives, and then further hoping I don't encounter problems hooking it up with my PCs really put a damper on my enthusiasm.

I consider myself tech-savvy enough to get it to work (After all, I've been fiddling with PCs and their associated peripherals since the late '80s... 8) ), but I guess I balked at the risk ($1,500 -- even $700 -- is no joke in a country where the minimum monthly wage is less than $200) and I chickened out :cry: and bought the safer ReadyNAS solution...

Anyway, going back to the ReadyNAS, it was easy to configure (it had those large fold-out color diagrams :lol: ), it should be easy to upgrade (to be validated in the future when I actually upgrade the drives), it provides good data security (hot-plug HDD trays definitely are a plus), but sadly transfer rates are not as good as I expected.

Using a Gigabit Ethernet LAN adapter (built-in Intel PRO 1000 MT) on my main PC (Dual Xeon 2.4GHz/Asus PP-DLW/1GB RAM/WinXP) with a D-Link 5-port Gigabit Switch (DGS-1005D) and 9014-byte Jumbo Frames (the maximum size the D-Link Switch supported), I was only able to get the following transfer rates (using the Infrant IOMeter test method):

Read transfer rate: 25MB/sec
Write transfer rate: 17MB/sec

(Without jumbo frames, the performance takes a hit... around 20 Read /12 Write MB/sec)

This is a significant difference from the ~40MB/sec (Read/Write) you can get from a FireWire 400 or USB 2.0 2.5" HDD enclosure with a decent hard drive.

Of course you have to factor in the built-in processor / RAM of the ReadyNAS appliance. At around 200+ MHz and 256MB, as well as the overhead for the RAID-5 hardware, it shouldn't be a surprise that it would be slower than the FireWire/USB enclosures, but I thought I could get more by upgrading my network to Gigabit Ethernet...

I guess I was too optimistic about the NAS performance, I was expecting something closer to the 30+MB/sec Write transfer I experienced when transfering files between two HP Proliant DL-380 Servers with Hardware RAID-5 over a Cisco Catalyst 2960G Gigabit Ethernet switch I encountered at work....

I also tried configuring my oldest working PC (AMD K6-460/Asus T2P4/96MB RAM) as a NAS running Linux, upgrading it with a Realtek 8169-based gigabit ethernet card in the process.

I've used both FreeNAS 0.66 and Ubuntu Linux 5.10 and here are the results of the IOMeter test (still tested from my main PC):

FreeNAS 0.66
Read/Write: 6MB/sec

Ubuntu Linux 5.10
Read/Write: 12MB/sec

FreeNAS was easier to install and use, unfortunately, it seems that it's network driver doesn't like my LAN card...

At least the results made me appreciate the ReadyNAS' performance.

As a point of reference, I tried the IOMeter test using my main PC and an older PC with a new D-Link gigabit ethernet card and a Promise UltraTX2 to support the 250GB hard drive installed (PIII-800MHz/Asus P3B-F/512MB RAM):

Read/Write: ~20MB/sec

I guess it would take a lot more hardware and tweaking to utilize the potential bandwidth of Gigabit Ethernet with a NAS solution.... sigh... Maybe I should have reconsider the FireWire-attached RAID solutions after all....

Well, I hope you aren't bored with my long and winding post and my tale will help others who want to experiment with NAS and RAID.

Regards.

^_^

Reply to Grifter357

Quote :

Hello all,

<snip>

Using a Gigabit Ethernet LAN adapter (built-in Intel PRO 1000 MT) on my main PC (Dual Xeon 2.4GHz/Asus PP-DLW/1GB RAM/WinXP) with a D-Link 5-port Gigabit Switch (DGS-1005D) and 9014-byte Jumbo Frames (the maximum size the D-Link Switch supported), I was only able to get the following transfer rates (using the Infrant IOMeter test method):

Read transfer rate: 25MB/sec
Write transfer rate: 17MB/sec

<snip>

^_^

Interesting data there. I have a question - did you have the chance to check the transfer rates withought the Switch in the middle? I'm wondering if the switch makes any difference (you never know)...

Reply to dimitrik

Quote :

p.s. I feel stupid, but why is my post centered instead of left-justified?

when i view this board at home it is all centered, but when i view it at work it is normal. very strange.

anyway this thread is far too boring and mature. Shouldn't we start bitching and moaning about whether he should have used an intel or amd cpu in it?
;-)

As a side issue Bill: it would be very interesting to see how slow a cpu you could put in the box without affecting the performance. That way people could see what the real minimum is. Can you try underclocking the cpu?

Reply to kevinherring

Quote :

I'm sorry to say i disagree with your article.

i say take a 6150 939 foxconn or some other 6150 mobo

ebay a 3200 for 50 to 65$

get 4 320gigs 7200.10 perpendiclar 100$ free shipping sometimes 95$ on newegg

get the cheapest case off of newegg under 30$ just pray that PSU don't go out. If so get a theremaltake 430 watt off of newegg.

this way you got screaming fast harddrives and 1 gig networking

I own all of these products. unfortantly i disagree with all of this i believe if your going need that much space you should get a E6300 duo core for 230$ i know it is expsive but it will be screaming fast on video encodding. Then we'd be way way more expsive. intel is the way to go for encodding.

or i say take a 6100 t-force socket 754 and a 1.8 ghz mobile turion processor with 1 mb l2 i have done this i know it works. i saw one not sell for 50 bucks on ebay. (i bought mine 50 days ago for 90$that only had 512k L2 cache

you can get 1 gig of ram and 2.4ghz turion(overclocked of course) 640gigs of space running raid 0

I hear people say that the harddrive runns faster than raptor. i cab only benchmark it at 66 mbs per second off of sisandra. your suppose to get like 85 or 88 i hear. Wil i firgure if you can get 135 mbs on raid 0 that is doin great.

The mobo,cpu,ram should not run you no more than 210$ i'd get patriot ram off of newegg 1 gig 2 x 512s

lol i call my OCed turion the 754 FX's he he.

i say the perfect sweet spot is every march a guy should ebay his stuff off. i bought a 2800 64 bit sempy and OC'd to 2.4 and 2.6 I just sold it for 11$ on ebay if i knew that i would have kept it and bought another mobo

I was beating a 3200 2.0ghz socket 939 running stock
with my lame 2800 sempron 1.6ghz OC to 2.4ghz

lol he paid 165 while i paid 75$ back in the day.

Reply to thiggins

Hey, I just wanted to thank you all for this article again. I built up a nas from an old Dell Dimension 8100 P4. I put a SCSI card in and attached it to an old DVD ROM server, and added an extra 160GB HD I had lying around to it.
I followed the directions in the article and BAM! Instant NAS.

I did however, use the UBUNTU 6.06 Lite Server edition. Its all command line stuff but it seems to work just fine.

Thanks again!

:trophy:

Reply to IVAces

Hi zyberwoof. Yes, there is a raid product that lets you use different sized drives. It is call un-raid by Lime Technology http://www.lime-technology.com

It has a parity drive, and does no stripping at all. The Parity drive must be equal to or larger than any other drive in the system. Then you can add drives when you want, up to 12 of them. That way you can pick up the Frys specials or the cheap after rebates drives to bring the cost low. Two additional benefits to this approach, is that for normal reading, only the drive that has the data need to be spinning. The rest can be powered down. Also, if you happen to lose 2 drives, then you only lose the data on those drives, not the whole set. This system is popular with Home Theater crowd.

Its drawbacks, are that it only supports a limited set of motherboards, and is a software raid solution. And it appears to be a one-man company, so support at times is spotty.

But it has the best of most worlds, when comparied to raid 5, etc.

Jeff

Reply to RocinanteX1

Here is a very good explanation between the RAID 0+1 and RAID 10.

http://en.wikipedia.org/wiki/RAID

If you have 4 drives, what is the advantage of going with RAID 5 over RAID 10?

Reply to WilliamT

Raid 5 uses less overhead than raid 10.

Reply to IVAces

That link was already posted.

Reply to jasonuscg

Just finishing up an article (draft is off to Tom's) comparing the Sempron 2200+ with a Duron 1.5 GHz. On Ubuntu with no-RAID5, makes a pretty big difference. On ClarkConnect (Fedora) not as big a difference and slower than Ubuntu.

This is a great question. I'm sure Tim and I will talk it over.

bill

Reply to billmeade

Is anyone here using RAID on direct attached storage?

It seems to me that NAS is often a stepping stone product for people. I have a friend who is a digital photographer with a Better Light (http://www.betterlight.com/) scan-back camera that takes images of up to 1 gigabyte in resolution.

I built him a NAS last year that has 2 TB of RAID5 in it. He's happy with it but not delighted. I think he needs something like the Wiebetech G5Jam+ which will let him RAID0 up to 12 SATA drives.

He came to my door needing a big store to organize his 40 linear feet of CDRs of backup images (40' measured across the CDs as they stand up with the thin edge facing you). The server I sold him does that job well. But along the way his need *shape*shifted* into wanting a lightning fast store to work on images in Photoshop with. That has to be an attached storage solution.

Firewire 800 will get to 50 megabytes per second. ESata will get up to 230 to 240 megabytes per second. That's what I'm learning. Is anyone playing with this direct attached stuff?

Or, how about infiniband?

bill

Reply to billmeade

We just installed an EMC Clarion X300 for our organization of 100 people and 5 servers. The Servers are attached with 2 fiber host bus adapters. We also opted for the LTO3 direct fiber attached tape vault. The Servers have 4GB/s throughput. The Tape vault backs up from the servers at 2GB/s.

I was utterly impressed at its speed.

EMC makes a budges line that uses SATAII drives that go up to 6TB+ of SATAII direct attached storage. Its the fastest thing I've seen so far.

Reply to IVAces

Quote :

Is anyone here using RAID on direct attached storage?

It seems to me that NAS is often a stepping stone product for people. I have a friend who is a digital photographer with a Better Light (http://www.betterlight.com/) scan-back camera that takes images of up to 1 gigabyte in resolution.

I built him a NAS last year that has 2 TB of RAID5 in it. He's happy with it but not delighted. I think he needs something like the Wiebetech G5Jam+ which will let him RAID0 up to 12 SATA drives.

He came to my door needing a big store to organize his 40 linear feet of CDRs of backup images (40' measured across the CDs as they stand up with the thin edge facing you). The server I sold him does that job well. But along the way his need *shape*shifted* into wanting a lightning fast store to work on images in Photoshop with. That has to be an attached storage solution.

Firewire 800 will get to 50 megabytes per second. ESata will get up to 230 to 240 megabytes per second. That's what I'm learning. Is anyone playing with this direct attached stuff?

Or, how about infiniband?

bill

I think a good raid controller, like an Areca will do the job fine. They are available in pci-x and pci-e.

The top model of them has 24 sata ports and supports not only common raid levels (0,1,5,10,...) but also raid 6.

Performance should be sufficient.
You can read a extensive review here (already more then a year old, but still a good reference point).

Reply to TomG23

I forget to say that this was a great article!

Reply to WilliamT

I'm a windows guy myself, so I'm not sure about the driver support, but what about utilizing a mobo with the ICHxR southbridge? It has integrated ethernet AND raid, and many 915 motherboards are < $100.

Pricing:

$75 915 Mobo with GB and RAID
$50 Celeron 326
$23 256MB RAM (333 MHz)
$80 PSU (as mentioned in article)
$30 Case (as mentioned in article)
$95x4 Seagate 320 GB SATA

==============
Total Price: $658 for 1TB RAID NAS

You could even go 128MB RAM since it's a file server, but you'd only save a couple bucks.

You might need XP to run it, but that's $80 and still a bit less than the article's estimate, and you have SATA instead of IDE.

I'm assuming there's a benefit to the configuration the author listed that I'm missing, but I figured I'd post anyway.

Reply to Whizzard9992

RAID 10 uses what is called redundancy rather than parity. Parity requires a parity bit to be written along with the data and thus takes more time.

Define - RAID (redundant array of independent disks; originally redundant array of inexpensive disks) is a way of storing the same data in different places (thus, redundantly) on multiple hard disks. By placing data on multiple disks, I/O (input/output) operations can overlap in a balanced way, improving performance. Since multiple disks increases the mean time between failures (MTBF), storing data redundantly also increases fault tolerance.

A RAID appears to the operating system to be a single logical hard disk. RAID employs the technique of disk striping, which involves partitioning each drive's storage space into units ranging from a sector (512 bytes) up to several megabytes. The stripes of all the disks are interleaved and addressed in order.

In a single-user system where large records, such as medical or other scientific images, are stored, the stripes are typically set up to be small (perhaps 512 bytes) so that a single record spans all disks and can be accessed quickly by reading all disks at the same time.
In a multi-user system, better performance requires establishing a stripe wide enough to hold the typical or maximum size record. This allows overlapped disk I/O across drives.

There are at least nine types of RAID plus a non-redundant array (RAID-0):

• RAID-0: This technique has striping but no redundancy of data. It offers the best performance but no fault-tolerance.

• RAID-1: This type is also known as disk mirroring and consists of at least two drives that duplicate the storage of data. There is no striping. Read performance is improved since either disk can be read at the same time. Write performance is the same as for single disk storage. RAID-1 provides the best performance and the best fault-tolerance in a multi-user system.

• RAID-2: This type uses striping across disks with some disks storing error checking and correcting (ECC) information. It has no advantage over RAID-3.

• RAID-3: This type uses striping and dedicates one drive to storing parity information. The embedded error checking (ECC) information is used to detect errors. Data recovery is accomplished by calculating the exclusive OR (XOR) of the information recorded on the other drives. Since an I/O operation addresses all drives at the same time, RAID-3 cannot overlap I/O. For this reason, RAID-3 is best for single-user systems with long record applications.

• RAID-4: This type uses large stripes, which means you can read records from any single drive. This allows you to take advantage of overlapped I/O for read operations. Since all write operations have to update the parity drive, no I/O overlapping is possible. RAID-4 offers no advantage over RAID-5.

• RAID-5: This type includes a rotating parity array, thus addressing the write limitation in RAID-4. Thus, all read and write operations can be overlapped. RAID-5 stores parity information but not redundant data (but parity information can be used to reconstruct data). RAID-5 requires at least three and usually five disks for the array. It's best for multi-user systems in which performance is not critical or which do few write operations.

• RAID-6: This type is similar to RAID-5 but includes a second parity scheme that is distributed across different drives and thus offers extremely high fault- and drive-failure tolerance.

• RAID-7: This type includes a real-time embedded operating system as a controller, caching via a high-speed bus, and other characteristics of a stand-alone computer. One vendor offers this system.

• RAID-10: Combining RAID-0 and RAID-1 is often referred to as RAID-10, which offers higher performance than RAID-1 but at much higher cost. There are two subtypes: In RAID-0+1, data is organized as stripes across multiple disks, and then the striped disk sets are mirrored. In RAID-1+0, the data is mirrored and the mirrors are striped.

• RAID-50 (or RAID-5+0): This type consists of a series of RAID-5 groups and striped in RAID-0 fashion to improve RAID-5 performance without reducing data protection.

• RAID-53 (or RAID-5+3): This type uses striping (in RAID-0 style) for RAID-3's virtual disk blocks. This offers higher performance than RAID-3 but at much higher cost.

• RAID-S (also known as Parity RAID): This is an alternate, proprietary method for striped parity RAID from EMC Symmetrix that is no longer in use on current equipment. It appears to be similar to RAID-5 with some performance enhancements as well as the enhancements that come from having a high-speed disk cache on the disk array.

Reply to jasonuscg

Quote :

RAID 10 uses what is called redundancy rather than parity. Parity requires a parity bit to be written along with the data and thus takes more time.

Define - RAID (redundant array of independent disks; originally redundant array of inexpensive disks) is a way of storing the same data in different places (thus, redundantly) on multiple hard disks. By placing data on multiple disks, I/O (input/output) operations can overlap in a balanced way, improving performance. Since multiple disks increases the mean time between failures (MTBF), storing data redundantly also increases fault tolerance.

A RAID appears to the operating system to be a single logical hard disk. RAID employs the technique of disk striping, which involves partitioning each drive's storage space into units ranging from a sector (512 bytes) up to several megabytes. The stripes of all the disks are interleaved and addressed in order.

In a single-user system where large records, such as medical or other scientific images, are stored, the stripes are typically set up to be small (perhaps 512 bytes) so that a single record spans all disks and can be accessed quickly by reading all disks at the same time.
In a multi-user system, better performance requires establishing a stripe wide enough to hold the typical or maximum size record. This allows overlapped disk I/O across drives.

There are at least nine types of RAID plus a non-redundant array (RAID-0):

• RAID-0: This technique has striping but no redundancy of data. It offers the best performance but no fault-tolerance.

• RAID-1: This type is also known as disk mirroring and consists of at least two drives that duplicate the storage of data. There is no striping. Read performance is improved since either disk can be read at the same time. Write performance is the same as for single disk storage. RAID-1 provides the best performance and the best fault-tolerance in a multi-user system.

• RAID-2: This type uses striping across disks with some disks storing error checking and correcting (ECC) information. It has no advantage over RAID-3.

• RAID-3: This type uses striping and dedicates one drive to storing parity information. The embedded error checking (ECC) information is used to detect errors. Data recovery is accomplished by calculating the exclusive OR (XOR) of the information recorded on the other drives. Since an I/O operation addresses all drives at the same time, RAID-3 cannot overlap I/O. For this reason, RAID-3 is best for single-user systems with long record applications.

• RAID-4: This type uses large stripes, which means you can read records from any single drive. This allows you to take advantage of overlapped I/O for read operations. Since all write operations have to update the parity drive, no I/O overlapping is possible. RAID-4 offers no advantage over RAID-5.

• RAID-5: This type includes a rotating parity array, thus addressing the write limitation in RAID-4. Thus, all read and write operations can be overlapped. RAID-5 stores parity information but not redundant data (but parity information can be used to reconstruct data). RAID-5 requires at least three and usually five disks for the array. It's best for multi-user systems in which performance is not critical or which do few write operations.

• RAID-6: This type is similar to RAID-5 but includes a second parity scheme that is distributed across different drives and thus offers extremely high fault- and drive-failure tolerance.

• RAID-7: This type includes a real-time embedded operating system as a controller, caching via a high-speed bus, and other characteristics of a stand-alone computer. One vendor offers this system.

• RAID-10: Combining RAID-0 and RAID-1 is often referred to as RAID-10, which offers higher performance than RAID-1 but at much higher cost. There are two subtypes: In RAID-0+1, data is organized as stripes across multiple disks, and then the striped disk sets are mirrored. In RAID-1+0, the data is mirrored and the mirrors are striped.

• RAID-50 (or RAID-5+0): This type consists of a series of RAID-5 groups and striped in RAID-0 fashion to improve RAID-5 performance without reducing data protection.

• RAID-53 (or RAID-5+3): This type uses striping (in RAID-0 style) for RAID-3's virtual disk blocks. This offers higher performance than RAID-3 but at much higher cost.

• RAID-S (also known as Parity RAID): This is an alternate, proprietary method for striped parity RAID from EMC Symmetrix that is no longer in use on current equipment. It appears to be similar to RAID-5 with some performance enhancements as well as the enhancements that come from having a high-speed disk cache on the disk array.

So RAID 10 faster than RAID 5 because it doesn't need to compute parity. Or is RAID 5 better because computing parity is less intensive than writing to redundant drives?

Thanks,
William

Reply to WilliamT

10 is much faster but costs much more to implement; more discs are required to achive a similar amount of space as 5. All of this really comes down to how much do you want to spend and how far to you want that money to go. Which do you want more of should determine how you should spend. Other than cost; speed, space, and reliability, these are what one should consider.

Reply to jasonuscg

Well I am going to show my ignorance here, but why not load the NAS with Windows for an OS?

Reply to vermin071

That's what I do, xp pro works fine for me, and if you don't have a domain, xp home is more than adaquate. It just costs more.

Reply to michaelahess

Quote :

Does the RAID card you have allow for other flavors of RAID?

I've been working with RAID devices for a long time. RAID 5, is not a performance wiz.

Now you see newer RAIDs, but back in the day, there were eccentially four flavors (five if you count RAID 3).

RAID 0 is the fastest performing. Sometimes call striping. Can be used on 2 to N disks. Any Read or Write is split amoung all the members of the RAID set. "Chunksize" is the amount of data read/written to/from each disk. Say you write a 1K file. And a 24Byte chunksize. And 4 disks in the set. The First chunk is sent to the first disk, second chunk to the second disk, and so on until you get to the last disk. Then you start over with the 5th chunk sent to the 1st disk again. The more members in the stripe set, the faster your performance (theoretically) because all members are writing at the same time.

RAID 1. Is sometimes called mirroring. Two disks. One disk is the exact duplicate of the other. When writing, whatever is sent to one disk, is sent to the exact same blocks on the other disk. The performance is slightly less than a single disk, because the controller has to wait for both disks to report back "I'm done" before continuing.

The downfall of RAID 0, is there is no redundancy. Loose one member of the stripeset, and all data is lost.

The downfall of RAID 1, is there isn't any performance gain over a single disk. Some controllers are smart enough to spread the disk reads over both disks. But that is impossible with writes.

The ultimate speed and redundancy is RAID 0+1. All disks are mirrored for redundancy, and all mirrors are striped for performance. The downfall of this is cost. Only half the raw disk space is truly available for use. You can as much as half the disks and still have data integrity. (As long as one member of all mirrorsets survive.)

In came RAID 5. It offers a compromise for both speed and redundancy. One member of the set is used for parity. Spacewise, you only waste one member's worth of space. But the cost is some performance. The controller has to always calculate parity for the Nth disk. Redundancy is also compromised. You can afford to loose one, and only one, disk from the set. Then the controller takes over rebuilding the data with the surviving member's info. Performance is OK for reading. But writing takes a hit with the parity calculations. Here, the more members the better as well. A person can make a strong case for a RAID 5 setup because under normal usage, disk reads are far more common then disk writes. Disks read perform nearly as well as a RAID 0 setup. But the disk drive costs are almost half of a RAID 0+1. If you were to loose a member, your reads would suffer as well, because the controller would have to reconstruct all the data on-the-fly, as you are doing the reads, to give you the data you are requesting. That is another reason why it behooves the person to replace a bad disk in RAID 5 set as quickly as possible.

But today... with the cost of disk space dropping like lead balloons. I would think your DIY project would get better performance with a 0+1 configuration. It would take all parity calculations out of the picture.

Also, Using IDE disks. You would have to be cognizant of the limitations of the IDE interface. If I remember correctly. If you have 2 disks on an IDE cable. You can only read or write from one disk at a time. If you set up a RAID set using IDE disks, then you only want one disk per bus.

One more thing.. Cacheing is important in any type of NAS or RAID scenario. The more memory one has available to cache read and write operations, the better. One of the reasons for RAID devices is performance. RAID devices are going to be hit hard and often (in theory). So a person wants all the performance they can get.

So.... I hope I've helped, and I'd be interested to see results of a RAID 0+1 setup compared to a RAID 5 setup.

Thank-you for your time.

Lyndon

The LSI Logic MegaRAID i4 allows RAID0, RAID1, and RAID5. The documentation says that it allows RAID10 (i.e., 1+0) but I've never been able to confirm that I've set the controller up correctly because the user interface is so rudimentary (i.e., character-based). I *think* I had it right, once, but the disk drive waste was working on my head. The server I was using is not doing much, so I saved off the data and converted to RAID5 which is simple to set up on an i4 or SATA-4 MegaRAID card.

But I have the drives, I can set up RAID10 on the 1 remainging machine I've got, and test that. I'll try that in background mode.

Thanks Lyndon for the pointers!

bill

Reply to billmeade

Quote :

Well I am going to show my ignorance here, but why not load the NAS with Windows for an OS?

Mostly because linux is free, and also because linux can be set up to just be a fileserver and not devote valuable resources to things like running a useless GUI, and because linux tends to have better network performance, and lastly because linux fans are even more extreme than mac fans. That sentence was crazy long; anyone else want to chime in?

Reply to megamojo

Quote :

....
and because linux tends to have better network performance, and lastly because linux fans are even more extreme than mac fans. That sentence was crazy long; anyone else want to chime in?

Well, the prevailing opinion here seems to be that windows has as good if not better network performance, since none of the linux solutions being discussed seem to really leverage GigE.

It does seem unlikely, but we need more data to be certain.

Of course Linux is a much more efficient OS, so it runs on minimal hardware but it seems that minimal hardware can't properly exploit the speed of GigE either.

So it could be that the way to go is, Linux for low end hardware, and for high end kit, consider windows as an option.

I can't believe I just wrote that 8O

Reply to dimitrik

Quote :

....
and because linux tends to have better network performance, and lastly because linux fans are even more extreme than mac fans. That sentence was crazy long; anyone else want to chime in?

Well, the prevailing opinion here seems to be that windows has as good if not better network performance, since none of the linux solutions being discussed seem to really leverage GigE.

It does seem unlikely, but we need more data to be certain.

Of course Linux is a much more efficient OS, so it runs on minimal hardware but it seems that minimal hardware can't properly exploit the speed of GigE either.

So it could be that the way to go is, Linux for low end hardware, and for high end kit, consider windows as an option.

I can't believe I just wrote that 8O

err, um,...

Quote :

I've recently upgraded my nas to the following - (don't cry)
AMD64 x2 3800, 1GB DDR2(800), 1GB nic, linuxfromscratch.org OS. Still running MD for raid5 - I've only done rough performance numbers of 90MB/s across the GiGe port sustained for 4 minutes.

Quote :

Here's my test results using the same parameters and 64k records in IOZone as your tests.
[code:1:e787017efa]
Write:
filesize (k) speed (MB/s)
32768 51.659
65536 54.018
131072 47.905
262144 28.789
524288 34.469
1048576 36.241

Read:
filesize (k) speed (MB/s)
32768 60.133
65536 58.101
131072 53.663
262144 48.462
524288 55.365
1048576 37.286[/code:1:e787017efa]

System specs on the server are:
athlonxp 2500
768 MB DDR400 (512+256)
160 PATA, 300 SATA, 320 SATA, 400 PATA
Asus A7N8X deluxe
Intel pro 1000MT nic
Slackware 10.2 with the 2.6 kernel and standard packages installed, Xserver rarely running
(no raid)

Both of those results are nothing to sneeze at, better than the setup in the article and better than any of the out-of-the-box solutions, and both of these are linux setups. j88per's setup is particularly impressive with his high end hardware, and my results represent what you can get with more modest hardware. How again is linux not leveraging GbE where windows is? I don't mean to pick a fight, my main box is windows and linux is just a server for me, it's just that in my experience you get better performance from linux regardless of hardware and can often get better performance with lesser hardware than a windows solution.

Reply to megamojo

Quote :

Both of those results are nothing to sneeze at, better than the setup in the article and better than any of the out-of-the-box solutions, and both of these are linux setups. j88per's setup is particularly impressive with his high end hardware, and my results represent what you can get with more modest hardware. How again is linux not leveraging GbE where windows is? I don't mean to pick a fight, my main box is windows and linux is just a server for me, it's just that in my experience you get better performance from linux regardless of hardware and can often get better performance with lesser hardware than a windows solution.

No worries - no fights here We learn by sharing. You make a very good point, but I do note that both of these setups are relatively high end - one is extremely high end (the Athlon X2 3800) and the other is nothing to sneeze at, although the equipment is not top of the line anymore.

And I wasn't happy to defend XP against Linux anyway. I was just saying that on high end hardware, Windows is a viable option, not the only or even the best.

From this data, I think we can conclude that the key determinant of perfromance on GigE is the hardware behind it (backplane/mobo, CPU, memory). The O/s will clearly also make a difference but perhaps less so.

Most of the ready made NAS kit uses relatively light hardware and therefore linux is the best choice. Simialrly if, I was building a NAS from my old P3 800MHz & 384MB PC100 RAM, I'd use Linux. The thing is at those hardware configurations the perfromance will only be so-so.

If you want really high performance it may be you need to use equipment like the examples you quote. In that instance we would need to benchmark performance with Linux vs. Windows, especially in light of the debate about filesystem performance with large vs. small files...

This is gonna make my head explode :?

Reply to dimitrik

Honestly, for a NAS, you could run MS-DOS and it wouldn't matter, as long as you can get your files.

I think what's important here is low cost and forward compatability. A file server's probably going to use like 1MB RAM at most for a buffer (usually only 8k). So you could run XP off of 64 MB RAM, but since you're not swapping you'll never know the difference.

I don't think performance is a real concern, either, unless you're talking Gbit versus Mbit networking. I think a Gbit connection on a NAS is a necessity, especially since they're so cheap nowadays.

As for RAID 10 versus RAID 5, RAID 5 offers EQUAL or BETTER Read speeds than RAID 10, depending on the controller. RAID 5 has slower WRITE speeds, but that usually only pertains to Random writes. Even mediocre controllers can write new RAID 5 stripes quickly. Parity only affects WRITE speeds, and it's only a real concern if you're changing data, not writing new data. Also note that there ARE controllers that will deliver RAID 10 speeds SLOWER than single drive performance, merely because they're not fast or smart enough to handle the work. In fact, you'll find MANY articles online stating that RAID 1 ALONE is slower than single-drive performance, let alone RAID 10 (which is more complex than RAID 1).

A RAID 5 array, you sacrifice 1 drive for parity. With a RAID 10 array, you sacrifice 1/2 of the total drive space. This means if you have 4 320 GB drives, you'll get ~1TB with RAID 5 and ~650 GB with RAID 10. With 6 320 GB drives you'll get ~1.6TB with RAID 5 and ~1TB with RAID 10.

So in short, RAID 5 offers more disk space with slower write speeds in certain scenarios. RAID 10 offers reliably fast reads AND writes (with a good controller). For a home NAS, you'll see little or no benefit to RAID 10 over RAID 5. On the other hand, if you wanted to run Windows off of an array, you'd be MUCH better off running RAID 1 (or RAID 10), unless you have a nice Adaptec adapter with a fast XOR engine (and you're talking US$700).

To conclude, if you want blazing RAID speeds, you really need a nice, dedicated adapter (not an on-motherboard solution). The on-mobo solutions offer good RAID 1 performance, but anything beyond that depends greatly on the type of RAID controller. A cheap (<$100) add-on RAID controller will probably offer the same performance as an on-mobo controller.

I'm still curious why Linux was chosen over Windows. Was it just the cheaper licensing? Author preference? I'm not flaming; I'm just genuinely curious.

Reply to Whizzard9992

Hopefully the author will chime in, but I'm guessing it's mostly licensing and the ability to configure it as a lightweight, headless server. It's kind of silly to say "Take old hardware you have lying around and then go buy a new copy of windows for $130 to run your fileserver." Performance differences are still up for debate, but I do have this to add. The last couple years at my college I hosted fairly large lan parties (~130 attendees all together, ~50 of them computer gamers) and had a file server running slackware. It was a 600Mhz pentium (III i think) with 384 mb of memory iirc. With all those clients it never bogged down and served up full 100Mbit speeds when it wasn'the getting totally hammered. I wish it had had gigabit but we were looking for a free solution.

The moral of the story is that you'd be surprised what you can do with low-end hardware. For a more in-depth article could you try a lighter weight linux distro than Ubuntu? Ubuntu is great if you want it to just work right away but it's not really ideal for a server. Slackware and Debian make great servers, or if you like lots of work Gentoo is great too. We all have our favorite distros but just try one that's lighter-weight than Ubuntu.

Reply to megamojo

GRRRR, double post.

Reply to megamojo

Quote :

Anyway, going back to the ReadyNAS, it was easy to configure (it had those large fold-out color diagrams :lol: ), it should be easy to upgrade (to be validated in the future when I actually upgrade the drives), it provides good data security (hot-plug HDD trays definitely are a plus), but sadly transfer rates are not as good as I expected.

Have you consulted the ReadyNAS Forums? http://www.infrant.com/forum/ They are really responsive over there.

And what version of the RAIDiator is your ReadyNAS NV running? They currently have 3.0 in beta, and it is extremely stable and the performance is a lot better.

Reply to ericdano

Quote :

Hopefully the author will chime in, but I'm guessing it's mostly licensing and the ability to configure it as a lightweight, headless server. It's kind of silly to say "Take old hardware you have lying around and then go buy a new copy of windows for $130 to run your fileserver." Performance differences are still up for debate, but I do have this to add. The last couple years at my college I hosted fairly large lan parties (~130 attendees all together, ~50 of them computer gamers) and had a file server running slackware. It was a 600Mhz pentium (III i think) with 384 mb of memory iirc. With all those clients it never bogged down and served up full 100Mbit speeds when it wasn'the getting totally hammered. I wish it had had gigabit but we were looking for a free solution.

The moral of the story is that you'd be surprised what you can do with low-end hardware. For a more in-depth article could you try a lighter weight linux distro than Ubuntu? Ubuntu is great if you want it to just work right away but it's not really ideal for a server. Slackware and Debian make great servers, or if you like lots of work Gentoo is great too. We all have our favorite distros but just try one that's lighter-weight than Ubuntu.

Yeah, you have some good points. The problem with windows is that just about EVERYTHING is some form of TSR. I haven't played with Vista, but it would be nice to see what's running on my box without having to decrypt the processes list in the task manager, and then find the appropriate setting or uninstaller. Hell, AIM triton takes up like 60+ MB when I'm not logged on. That's rediculous.

The problem with Linux (I've found) is that you can't just dive right into it like you can with windows. For example, if I took my old system, I might spend 3 hours installing a Linux build just to find out the linux drivers aren't compatable with the build I installed. I just haven't had the time, or need, to explore Linux that deeply (other than VMWare ). It would be nice if MS would release lighter versions of windows for special app servers, like NAS. Then again, they wouldn't be the money-hungry conglomerate they are now if they thought like that, would they?

*lights a candle on his M$ shrine and prays for forgiveness* :lol:

Anyway I love windows, for all of its nuances it's a great desktop OS. It would have been nice to see a windows NAS version in the article somewehere for all of us *nix neophytes. For me, it seems that the lack of driver support for Linux ultimately drove up the cost of the system because certain linux-capable peripherals had to be purchased (feel free to correct me if I've made the wrong assumption).

Reply to Whizzard9992

I completely agree with you. Linux is great once you have it running, but i've spent hours just trying to get one thing to work. When I installed my first S-ATA drive in that machine the system just would not see it. After hours on google and linux forums i finally added 1 line consisting of about 20 characters to a single config file. It would be great if MS would release a lightweight server version of windows. They do have a server OS, but it's definitely not lightweight and not really aimed at this purpose.

Reply to megamojo

Quote :

<snip>

Interesting data there. I have a question - did you have the chance to check the transfer rates withought the Switch in the middle? I'm wondering if the switch makes any difference (you never know)...

Hmmm... I haven't done that yet, since even if it turned out faster, that setup (main PC back-to-back with NAS over cross-cable) would be useless for me...

The switch certainly plays a major role in the transfer rate, since jumbo frame support would be crucial to higher transfer rates. I got a D-link 8-port DGS-1008D which should also support jumbo frames (according to info on the 'net), but my particular unit doesn't support jumbo frames too well. If I connect the ReadyNAS and my main PC on it, I can read data from the NAS but cannot write data to it (copy errors) unless I disable jumbo frames on my PC. I had to re-arrange the network so that the PCs I need to access the NAS with jumbo frames were together on my 5-port D-link DGS-1005D while the rest were connected to the cascaded 8-port switch....

Regards,

^_^

Reply to Grifter357

Quote :

<snip>

Have you consulted the ReadyNAS Forums? http://www.infrant.com/forum/ They are really responsive over there.

And what version of the RAIDiator is your ReadyNAS NV running? They currently have 3.0 in beta, and it is extremely stable and the performance is a lot better.

I'm currently using RAIDiator v2.00c1-p9. I haven't checked back at the ReadyNAS forums since I got my jumbo frames working since the max transfer rates published by Infrant for the ReadyNAS NV (I think it was 34 Read /22 Write MB/sec) assumes 16K jumbo frames.

I'll check out the new RAIDiator versions and see if I can get more performance from it.

Thanks!

^_^

Reply to Grifter357

There are different versions of that switch. The C3 and higher hardware versions support jumbo frames, the older ones do not. I am in the exact same situation as you since I have the C1 version. I emailed tech support and they told me to call customer support and ask for a version swap, but after being on hold forever I was told they can only replace it if it is defective. Understandable, but I thought it was worth a try to call them from what tech support had emailed to me.

Reply to megamojo

Quote :

[snip]
I'm still curious why Linux was chosen over Windows. Was it just the cheaper licensing? Author preference? I'm not flaming; I'm just genuinely curious.

Reasons behind choosing Linux:

#1 I think Tim Higgins' idea was to collect all the pieces of a NAS from the basement and see how good the performance was. Linux makes sense because it is free.

#2 I have been using RAID on Linux exclusively. I've worked with SUSE, Linspire 5, ClarkConnect, Ubuntu, Gentoo, and Open BSD.

For this article, we just wanted to compare the cheapest system we could to the commercial boxes.

Tim had me write a second article which should come out within a couple weeks, in that article we do compare XP Pro to Ubuntu and ClarkConnect. Stay tuned!

bill meade

Reply to billmeade

Quote :

[snip]
The problem with Linux (I've found) is that you can't just dive right into it like you can with windows. For example, if I took my old system, I might spend 3 hours installing a Linux build just to find out the linux drivers aren't compatable with the build I installed.

Not true with Ubuntu 6.06 Desktop. That is why I used it. I'm just AMAZED at how great it is at installing on disparate hardware. I challenge you to throw together a piece of crap system and see if Ubuntu won't install in one go. I'm down to 31 minutes per install including time to format a 300 megabyte hard drive.

*Point* Ubuntu brings Windows-like "dive-in-ability" to Linux.

Quote :

[snip] For me, it seems that the lack of driver support for Linux ultimately drove up the cost of the system because certain linux-capable peripherals had to be purchased (feel free to correct me if I've made the wrong assumption).

You may not be commenting on the system used for the article. But then again, if you are, Linux didn't affect the cost. It did affect which builds were tested.

THE BIG IDEA of hardware RAID to me is that the hardware card gives you independence from the operating system's implementation nuances. The MegaRAID i4 will work fine with XP (yes, I wish I'd benchmarked it, but stay tuned), Ubuntu, as well as other Linux build (Fedora is the exception. I think with the 2.6 kernel they yanked support for the ATA LSI Logic cards. This prevented me from comparing ClarkConnect to the other operating systems.

I have a drawer full of MegaRAID i4s that I'd picked from a Tom's review a couple years ago. I used the i4 because I had it in hand.

bill

Reply to billmeade

Quote :

*Point* Ubuntu brings Windows-like "dive-in-ability" to Linux.

And with that comes a portion of the bloat that windows has. Not as much, but there's no point to installing or running gnome or kde on a server.

Quote :

I think with the 2.6 kernel they yanked support for the ATA LSI Logic cards. This prevented me from comparing ClarkConnect to the other operating systems.

bill

When you say they do you mean the Redhat/Fedora Core people or Linux in general? If you mean Linux in general and because of this your Ubuntu was running the 2.4 kernel, that's a major problem for this article. When I moved my system to 2.6 I saw about a 30% improvement in transfer speeds. I've seen benchmarks on high end hardware showing an 89% difference between 2.4 and 2.6 for samba filesharing. If the system in the article was using the 2.4 kernel, using 2.6 for the 2nd article is a must.

Reply to megamojo

Quote :

When you say they do you mean the Redhat/Fedora Core people or Linux in general?

Fedora pulled the support. So Fedora-based builds (ClarkConnect is Fedora based) won't work with the MegaRAID i4 card.

Quote :

If you mean Linux in general and because of this your Ubuntu was running the 2.4 kernel, that's a major problem for this article. When I moved my system to 2.6 I saw about a 30% improvement in transfer speeds. I've seen benchmarks on high end hardware showing an 89% difference between 2.4 and 2.6 for samba filesharing. If the system in the article was using the 2.4 kernel, using 2.6 for the 2nd article is a must.

Ubuntu 6.06 Desktop was the stock ISO with 2.6.15.

I am definitely making a list of things to look at in possible follow on articles. The biggest Ubuntu-related issue is the server vs. desktop version comparison. But, any ideas appreciated on what you'd like to see explored. Everyone, please chime in or email me (bill@basicip.com) to let me know what you wish you could see profiled.

bill

Reply to billmeade

Thanks for the great replies! It paints a better picture.

It's a cool article, and I like the concept. I'll have to give Ubuntu a try.

I'm interested to see the next article. If you could, I'd really like to see how well the new ICH8R Matrix RAID performs. 6 SATA ports built-in could help give you more storage for the same price with a comperable 4-port system.

Example:
4x 750 GB RAID 5: 2.2 TB @ $1600
6x 400 GB RAID 5: 2.0 TB @ $840

Thanks!

Reply to Whizzard9992

So after reading Bill's article I've started thinking about setting up a RAID 5 fileserver at home. I have over 1TB of audio/video/photos. I can't keep adding drives to my PC because of heat/controller issues, I need backups, and a server is better long term solution.

The question I'm facing is: Should I buy a ready made solution? Build one from old kit? Or build a brand new one?

The ready made solutions (e.g. Infrant ReadyNAS NV), seem to offer so-so perfromance. Cost about $1000 (500GBP) +HDD's. This is the easiest solution, but not the best value for money because of perfromance and lack of expandability beyond 4 drives.

The kit I have lying around is pretty old. A P3 800, 384MB SDRAM, an Intel mobo (100MHz bus) and a 10/100 NIC. I could add a RAID card, some cooling and set up a basic linux box for say $200+HDD's. This would support 4 disks and have weak performance but the cost is lowest.

The best case scenario is to set up a brand new box, using mid-range kit, with a linux server, which according to posts on this thead will give by far the best performance. Unfortunately this will cost almost $1500 (700GBP).
But speeds will be 3 times better than the readyNAS and 5-6 times faster than the low end box. Also with an 8 channel controller, there's plenty of room to expand.

I'd be grateful if anyone has had experience with the low end setup, otherwise I'm leaning toward setting up the new box, however my budget will feel the pain

Any advice will be appreciated!

Reply to dimitrik

That setup would be more than fine, just add some hd's. You may need to buy another controller if you fill all the ide ports, but I'd just stick with software raid. It may not be the fastest on the planet but it will probably do you all right. I have plenty of smaller servers with 800-1000mhz PIII's and they all run software raid and server2k3, so I know a good ol PIII can handle it

Reply to michaelahess

Quote :

So after reading Bill's article I've started thinking about setting up a RAID 5 fileserver at home. I have over 1TB of audio/video/photos. I can't keep adding drives to my PC because of heat/controller issues, I need backups, and a server is better long term solution.

The question I'm facing is: Should I buy a ready made solution? Build one from old kit? Or build a brand new one?

I say build one from parts you have, and see if you are happy with it. If you are not happy with it, it is a lot easier to get your money out of a running NAS than you would think. Almost *sales by osmosis*. I built a 2 terabyte NAS a year ago just to see what would happen.

Something happens to you when you've got an "extra" NAS running. You begin to hear friends and neighbors complaining about their storage problems. Next thing I knew, I'd sold my 2TB server to a friend who does EXTREME digital photography (http://www.pixellight.com).

The biggest problem is how to you get a significant amount of storage volume. Striping drives is just so excellent for having 1 very large easy to remember storage space. For this, the hardware RAID card is the perfect tool. But, it looks like webmin can stripe drives into software RAID. So maybe put clarkconnect on the parts you have, then do an apt-get install webmin to install webmin and play with it.

But, the one thing you get with the ReadyNAS is that it will power itself down when you don't need it. And, power itself up when you do need it. I think that is pretty compelling.

bill meade

Reply to billmeade

Quote :

<snip>
I have plenty of smaller servers with 800-1000mhz PIII's and they all run software raid and server2k3, so I know a good ol PIII can handle it

Quote :

I say build one from parts you have, and see if you are happy with it. If you are not happy with it, it is a lot easier to get your money out of a running NAS than you would think.
<snip>

Thanks guys, that helps put things in perspective for me. All I need is a case and a RAID card, which is pretty easy to get. I assume if I ever want to upgrade the system, the array will be ok, as long as I use the same controller.

Quote :

But, the one thing you get with the ReadyNAS is that it will power itself down when you don't need it. And, power itself up when you do need it. I think that is pretty compelling.

That is actually pretty compelling. I assumed I could get power management and 'Wake on LAN' to work on the linux box, but I never tried that before so may be completely off-base.
I guess keeping the thing on 24/7 will have some impact on the disks' life.

Reply to dimitrik

Just read an article about the Norco DS-1220 over the weekend, http://www.ehomeupgrade.com/entry/ [...] ds-1220_12

Going to get one to build my NAS with one of my retired systems this week. It says it will do RAID5 and 12 bays give me plenty of rooms to add more drives later. With old parts plus the new array, I should be able to build a cheap 2TB NAS for less than two grand.

Reply to mobileHTPC

Hah, a 2TB with ease for under $2k. Too bad it does not support more raid options

Reply to jasonuscg

Quote :

The ready made solutions (e.g. Infrant ReadyNAS NV), seem to offer so-so perfromance. Cost about $1000 (500GBP) +HDD's. This is the easiest solution, but not the best value for money because of perfromance and lack of expandability beyond 4 drives.

Not true at all. The ReadyNAS NV can be expanded via USB, or, if you want to replace all the drives (one at a time, let it rebuild, then another, and so on) it will expand the array. So, if you start with 4 250 gig drives, and decide to upgrade to 4 500 gig drives, you can.

Size, heat, and noise there is no comparison. The ReadyNAS NV wins. Plus, it will draw less power as well. And it's going to be smaller than any PC you hack together.

Reply to ericdano

Quote :

Not true at all. The ReadyNAS NV can be expanded via USB, or, if you want to replace all the drives (one at a time, let it rebuild, then another, and so on) it will expand the array. So, if you start with 4 250 gig drives, and decide to upgrade to 4 500 gig drives, you can.

Size, heat, and noise there is no comparison. The ReadyNAS NV wins. Plus, it will draw less power as well. And it's going to be smaller than any PC you hack together.

Thanks, I'd really like to accept that. I have however heard some conflicting reports - people complaining about noise and particularly speed. But given the ease and the power managment I agree it's worth considering.

Reply to dimitrik

Build a Cheap and Fast RAID 5 NAS - Page 2

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