Build a Cheap and Fast RAID 5 NAS

[Guest]

An excellent article. I have been trying to setup something like this. I just went thru 2 weeks of trying to get software raid 5 to work in Ubuntu. I searched the net for how-to or step by step instructions and could only find bits and pieces. Nothing worked. Linux users need to remember that us wanna bees don't know even the slightest of commands! In every article I found, they assumed you knew "some" basic commands. I tried reading and learning, but I couldn't find a good learner for linux. Anyway, having decided to do a hardware raid 5 with Ubuntu desktop seemed like my only hope. Then I find this article here, and it is exactly the way EVERY article should be done, step by step, assuming the reader knows nothing. This article is VERY good and thorough! Congratulations Benjamin Webb, you did a great job! -Blueuniform

 

[Guest]

interesting article, but the beauty of linux software RAID5 is that an array rebuild will happen automatically when you replace the faulty drive (well you have to tell it that you replaced the drive using mdadm). you can even simulate a failure and then watch it rebuild the array to get an idea of how your system will respond under different scenarios. here's a snippet of what needs to be done to replace the missing drive/partition:

Rebuilding:

To remove the failed partition and add the new parition:
mdadm /dev/mdX -r /dev/sdYZ -a /dev/sdYZ

where X is the array number (0,1,etc) and YZ is your disk/partition (sda3 for example)

e.g.:
mdadm /dev/md0 -r /dev/sde3 -a /dev/sdr3
(where sde3 is the 3rd partition on your faulty drive, and sdr3 is the 3rd partition on the new drive)


Watch the automatic reconstruction run with:
watch -n1 cat /proc/mdstat

 

[Guest]

I understand that people fear the console commands. It can be a bit scary at first. But mdadm is pretty simple when you're used to console apps and a little bit of linux. It's mostly just mdadm and such. I currently run two software raids with 7 and 5 disks.

 

[Guest]

i believe his concerns with software raid5 were not just the rebuilding points. i believe he liked the fact that if the os drive took a crap, he could take the card and array and move it to any operating computer and it would power up and work. if you lose the operating system that wrote the software raid array, you have lost the array.

 

[Guest]

Hi! I have now suffered RAID5 failure due to one failed disk and the status now of my RAID5 controller is degraded.. Is it safe to rebuild the same failed drive? we're using MegaRAID WEBIOS controller? will the data be lost if we do this?

We are in the hesitation mode of doing this..

I hope this will be stressed out...thanks for your help!

 

[Guest]

re: above

Do not try to rebuild your raid array with a drive that already failed. I cannot say 100% b/c I do not use MegaRAID controllers, but it is telling you to get a new drive. Go get a new drive and follow the rebuild instructions for your controller. It is trying to save you.... don't outsmart yourself here You will regret it.