6x 36GB Raptors in RAID 10/01 --read performance vs RAID 0

[Order]

The title pretty much says it all. I'd be using an Areca 12xx PCI-E with 256MB cache. I'd love to put them all in RAID 0 but, you know...I'd like my data to exist for a little while http://www.xtremesystems.org/forums/images/smilies/smile.gif. Does anyone have experience with this configuration or at least a similar one? I don't want to use RAID 3,4,5, or 6. I'm leaning more toward 3 striped RAID 1 arrays so I guess that makes it RAID 10 (1+0).

[acascianelli]

I would rather use RAID5, with one hotspare. I've done RAID 0 with 12 drives I think it was before, it was just for grins though.

[poison123]

Good lord you gonna use this to backup/protect money data or something? Anything less and this is extreme overkill.

[Order]

Although the system is mostly for gaming (Supreme Commander...holy shit), I do lots of massive QuickPAR creations and repairs and from what I know it is extremely I/O intensive. I've been downloading high-definition videos, some of which are over 18GB in size, and my system literally crawls while it is repairing one. Although my CPU graph shows less than 60% utilization, my hard drive sounds like its grinding meat, lol. Various things that I've read show that an array will significantly increase both the performance of the PAR operations and allow for multitasking.

[protias]

If you are going to use Raid 3, it would probably benefit you to go Raid 5 instead. That way if a drive dies, you can recover the array a whole lot easier than from Raid 3. Depending on the amount of drives, you may benefit using Raid 6 for uptime anyway. It's not as fast as Raid 5, but if 2 drives go down, your data is still intact.

Edit: I see it is 6x36GB drives (forgive me, been real busy at work and trying to do [H] at the same time, so work is cutting into my [H] time :() Raid 5 would probably be your best bet.

[unhappy_mage]

If you are going to use Raid 3, it would probably benefit you to go Raid 5 instead. That way if a drive dies, you can recover the array a whole lot easier than from Raid 3. Depending on the amount of drives, you may benefit using Raid 6 for uptime anyway. It's not as fast as Raid 5, but if 2 drives go down, your data is still intact.
Raid 3 and 5 are equivalent in terms of recoverability.

Order: It doesn't *literally* crawl. It *figuratively* crawls ;) What's the typical percentage of parity and block size in those PAR2 files? I'm trying to recreate awful speeds on my machine and having no luck :p

[protias]

Raid 3 and 5 are equivalent in terms of recoverability.

Order: It doesn't *literally* crawl. It *figuratively* crawls ;) What's the typical percentage of parity and block size in those PAR2 files? I'm trying to recreate awful speeds on my machine and having no luck :p

Well, I mean, the parity bit is saved over all the drives in Raid 5 where in Raid 3 it is saved on a single drive. So wouldn't this make Raid 3 a bit worse of a decision if the parity drive took a dive?

[unhappy_mage]

Well, I mean, the parity bit is saved over all the drives in Raid 5 where in Raid 3 it is saved on a single drive. So wouldn't this make Raid 3 a bit worse of a decision if the parity drive took a dive?

No. The recovery process is exactly the same - calculate the XOR of the remaining disks, and write it to the new blank disk. The difference is that the single parity drive in raid 3 may be more likely to die, because it's involved in all write operations so there's more load on it.

A side note - you did mention six disks, so I think it precludes this - but for the love of god don't buy the 5-port netcell sata cards. A special level of hell is reserved for those. They generally don't recover from disk failures, which is the whole point of raid 3. They claim distinct performance advantages, but I haven't seen anything even remotely bearing that out. There's a reason they're apparently out of business.

[taqueso]

Read speeds should be similar to RAID-0, writes a little less than 1/2 RAID-0. I think you are right to avoid RAID-5/etc.

[Order]

I appreciate the replies. The block sizes for the largest ones are around 100MB each. Average size is approximately 50MB. Don't worry, I'm planning to go with Areca or Adaptec (the latter is only if I decide I want SAS in the future as it will be their SAS adapter).