How to setup a software RAID 5 using IDE drives?

kitek · 03-17-2007, 06:44 PM

New Raid user here. I understand how it works for the most part but I just need help/suggestions on how to set it up. When planning the design of the webserver, I failed to notice what type of drives I needed and the correct MB. I purchased a MB that is compatible with RAID SATA. I purchased IDE drives

. So I'm having to settle for a software raid. Heres my specs.

AMD Opteron Duel Core Box 165
2GB Ram Expandable to 4GB
3 300GB Western digital 7200RPM IDE Drives
I want to use Centos 4.4

I'll use some sort of control panel. Any suggested free ones would be appreciated until I can afford Cpanel. Nuonce has Blue Quartz but thats another issue.

I understand that I need to make software Raid partitons to create a Raid device. But what other partitions and how much space for each? Again I want to setup a RAID 5 array.

/
/boot
/ext
/swap
Raid

Also if all the boot and other partitions are only on the first disk, what happens if that first drive fails? When a drive does fail on a software raid, how do you start the recover process?

Thanks in Advance.

Quakeboy02 · 03-17-2007, 07:08 PM

Before you get too bummed out, the RAID on that mobo was almost surely FakeRaid; i.e. a modified software RAID. Is it too late to take the drives back, or did you open them already?

One issue that you will have to deal with, though, is that by putting 3 drives on 2 cables, you will have 2 drives that are effectively running at about half throughput speed. You might consider getting a PCI IDE card to put two of the drives on, and put the third drive and your DVD drive on your two mobo cables.

Now, as to how to deal with your 3 drives in a bootable software RAID5, you're asking the right questions. But let me ask you essentially the same question I asked someone else in another thread: do you need RAID5, or do you just want to use it? Do your really have 600GB of data that you want to serve? Could you get by with a RAID1 with 300GB and have the 3rd drive as a fail drive? Do you even need the reliability that RAID5 would hopefully afford. What are the real-world implications of a drive failing on you, given the handicaps already before you? I suspect that the data isn't terribly valuable, since you're willing to accept the handicaps and are unwilling to spend your way past them.

kitek · 03-17-2007, 07:30 PM

Quote:

Originally Posted by Quakeboy02

Before you get too bummed out, the RAID on that mobo was almost surely FakeRaid; i.e. a modified software RAID. Is it too late to take the drives back, or did you open them already?

One issue that you will have to deal with, though, is that by putting 3 drives on 2 cables, you will have 2 drives that are effectively running at about half throughput speed. You might consider getting a PCI IDE card to put two of the drives on, and put the third drive and your DVD drive on your two mobo cables.

Now, as to how to deal with your 3 drives in a bootable software RAID5, you're asking the right questions. But let me ask you essentially the same question I asked someone else in another thread: do you need RAID5, or do you just want to use it? Do your really have 600GB of data that you want to serve? Could you get by with a RAID1 with 300GB and have the 3rd drive as a fail drive? Do you even need the reliability that RAID5 would hopefully afford. What are the real-world implications of a drive failing on you, given the handicaps already before you? I suspect that the data isn't terribly valuable, since you're willing to accept the handicaps and are unwilling to spend your way past them.

I had already had the drives for a month installed in this pc before I realized it was the wrong setup. I plan on using this server to start some web hosting. I also plan to make another for a dedicated MySQL server for another project. So I will need 600GB+ and the data will be valuable of course. I am willing to spend more to get past the handicaps however, I would like to get this one online and going and then I will build another with my mistakes kept in mind. Ultimatly I would retire this server and transfer the data to the new and correctly built server. Budget wise at this point I'm really stuck with this as a starting box. I'm glad you mentioned the drives running on 2 cables. I will definetly add a PCI IDE card.