Building a RAID 5 Array - Need Help! - NAS / RAID

ducats

June 11, 2010 7:56:37 PM

Hi, I am wondering what the best setup for a RAID 5 array within these parameters is. I have two issues:

1. Right now, I am debating between FreeNAS and Windows XP software RAID. I know much more about winXP's RAID controller (mainly because of the article here on tomshardware!). I want to be able to read/rebuild the array on any mobo, chipset, and so on. I know winXP can do this. Is freeNAS' controller as versatile as winXP's RAID controller (i.e. could I rebuild/read the array on any PC running freeNAS)? Is there anything else which might make freeNAS a better choice? Is there a third, better option which I'm not considering? I am fine with linux, so that's not an issue.

2. I already have one 1.5tb drive, and I can only afford two more. Could I start the array in a degraded state, copy the files to it, then rebuild with the third drive? Is either software RAID controller preferable in this situation? Basically, what is the best way to make a RAID 5 array happen? I don't have anywhere else to put the data.

Here is what I want in the end:
3tb (3x1.5tb) RAID 5 array
ability to read/rebuild array on any mobo/chipset etc.
software RAID (either XP or freeNAS, or anything else which satisfies the above requirements)

Thanks!

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zfsnoobman

June 14, 2010 2:09:27 AM

In an effort to not spam these forums with ZFS related posts (propaganda?). I'll link to this post (see my reply):
http://www.tomshardware.com/forum/258741-32-does-this#t...

Same setup but instead of using mirror raid5 you use RaidZ (which has the same three drive parity setup). It is a software raid solution, but it has many many advantages over standard raid (see above link).

Also yes you can start with the system degraded. Currently I'm building that exact same system for myself.

I have 2x 1.5TB drives currently set up in raid1 on Windows 7. What I will be doing is buying a third, using two of the drives as a degraded raidz, copy the data and then use the last drive to build parity. I know its pretty dangerous, but I can't afford another drive. When I'm done I'll post detailed instructions on how to do it. I've been testing these steps in Virtual Box and it look pretty doable right now:

Current raid1 drives are called A, B, new blank drive is called C.

Step 1: Break the mirror of A & B inside Windows 7
Step 2: Purchase the new C hard drive, and install it in the case.
Step 3: Boot to OpenSolaris
Step 4: Make sure you've gone out and installed the NTFS driver:
http://blogs.sun.com/pradhap/entry/mounting_ntfs_partit...
Step 5: mount drive A: mount -F ntfs /dev/dsk/c0t0d0p0 /mnt
Step 6: create a "dummy" drive as a sparse file: mkfile -n
1500G /foo
Step 7: create the new RaidZ array, using the dummy drive:
zpool create tank raidz c0t1d0 c0t2d0 /foo
Step 8: remove the dummy drive: zpool offline tank /foo
Step 9: copy all the data from the NTFS drive to the new drive:
cd /mnt; cp -rp . /tank
Step 10: kill the NTFS partition info: run "format" and delete
everything
Step 11: add the erased NTFS drive to the new raidZ: zpool
replace -f tank /foo c0t0d0
Step 12: delete the dummy file: rm /foo

Since this uses all opensource software, you can mount this FS on any OS that supports it. (Linux supports it through FUSE, but the performance is not as good). And you can easily move the drives to a new computer.