Software RAID5, this look normal?

[[LYL]Homer]

I've been having issues with my media server's RAID5 array so this weekend I copied everything off, deleted the array, built a new array, and copied everything back in hopes of an improvement.

Issue #1:
I've noticed that it seems to have slowed down over the last month or so, copy/move times seem acceptable still when going from the RAID5 array to other drives. But it seems 4x slower going the other way. My recollection is that it didn't seem significantly different in the past.

As you can see it's all over the place. It's 4x320gb 7200.10 drives running off the motherboard's 4 SATA ports on the nVidia 6150/430 chipset. Specs are system #2 in my sig. The nVidia MediaShield software says it's a healthy array.

RAID5 array:
http://img76.imageshack.us/img76/2083/raid5yu6.jpg

For comparison here are two other drives on the same machine. First, an IDE WD800JB which is the OS drive.
http://img75.imageshack.us/img75/8554/wd800jbft2.jpg

...and a 7200.10 running off a Rosewill PCIe 2 port SATA card.
http://img260.imageshack.us/img260/7159/720010fv7.jpg

Issue #2:
I've had an issue with mapping to the RAID5 array. Other drives on the server are not a problem, just this one. I had hoped this 'new' array would solve this issue. Something with the RAID, or Linksys router, or Windows admin rights/permissions? I'm baffled.

Browsing from Explorer over the network to the \\Server\Media (M)\ it goes to the hourglass and times out with the error message "\\Server\Media (M) is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. Not enough server storage is available to process this command." Trying to map the drive gives a similar result.

Here's some more history, in case anyone can help - http://www.hardforum.com/showthread.php?t=1172722

edit: BTW, those are the long test results in HDTach.

[gigabyte1024]

I'd say this is what you get with software raid.
Your numbers are going to be all over the place depending on what else the machine is doing at the time.

As for the share, what happens when you specifically share a folder, can you access that?

[Madwand]

I have an nForce 430/6150 combination on an Asus A8N-VM CSM. I've found the RAID 5 on it to be a bit quirky. I've never gotten good write performance from 4-drive NV RAID 5.

At times I've gotten great read and write performance from 3-drive NV RAID 5, and then re-built the same array and gotten bad write performance. Re-built it again, and gotten good write performance. Write performance is always the real challenge with RAID 5 implementations, especially cheap ones.

I think every time I've gotten good write performance with NV RAID 5, it's been:

3 drives
32k stripe size
created within RAID BIOS, not Raid Tool.

The following happens to show good (but unstable) read performance with 4-drive NV RAID 5, and good (and stable) read performance with 3-drive NV RAID 5. However, it doesn't show the write performance with RAID 5, and as far as I recall, I've never gotten good write performance with this NV RAID 5 performance using 4 drives (despite several attempts of course).

http://i89.photobucket.com/albums/k203/Madwand0/nvr5-4drive-vs-3-read.png

There are several potential ways out:

1. Try re-creation of the array from the BIOS
(don't bother populating it for testing, it doesn't matter with HD Tach)
2. Go to 3-drive RAID 5 as has worked for me
3. Go to 3 or 4-drive RAID 0
4. Go to a new add-on controller, e.g. Highpoint 2300.

Finally, HD Tach is not a good tool for such measurements -- it has strange reactions sometimes to some RAID implementations. And of course it tells you nothing about write performance. I'd rely on simple very large file copies from one drive/array to another more than I'd HD Tach.

ATTO runs at the file system level, so it does matter what else is on the drive at the time of the test. It can also give some very wrong results depending on the circumstances and options, etc. However, it's simple and can give some useful results -- when those results are correlated with other results such as file copies for validation.

E.g., nForce 430 3-drive RAID 5, 32k stripe size (on Vista):

http://i89.photobucket.com/albums/k203/Madwand0/nvr5-3drive-atto.png

[[LYL]Homer]

edit: had the wife check browsing/mapping to the folder, no luck.

iirc I used 64k clusters in the nVidia Mediashiled setup.


Here's an ATTO pic: :(

http://img488.imageshack.us/img488/3395/raid5attodx1.jpg

It may come to rebuilding the RAID5 array under the BIOS, but what 4 port RAID5 cards does anyone suggest? PCIe 1x or 4x preferred, but with some major rearrangment I might be able to go PCI.

[gigabyte1024]

Homer;1030885389']edit: had the wife check browsing/mapping to the folder, no luck.

It may come to rebuilding the RAID5 array under the BIOS, but what 4 port RAID5 cards does anyone suggest? PCIe 1x or 4x preferred, but with some major rearrangment I might be able to go PCI.

If you're gonna do it, do it right. PCIe is the only way to go when you want bandwidth.
PCI is crap (well, relativly anyway) and it's only there for backward compatibility.

[[LYL]Homer]

Well, I spent last night trying about a dozen different combos - 4 drive RAID 5 with drive order swapped around, 3 drive RAID 5 taking out one drive at a time 4 times to see if one drive was causing the issue (nope), 4 drive RAID 0, RAID 1, each with different cluster sizes. Typical write for ANY configuration was 3000-6600, and read was 55,000-75,000 for 16-1024k transfers. In other words, I couldn't even repeat something as good as my first ATTO screenshot above in any configuration. The write times are just pathetic.

The real bummer here is that a few weeks ago the seat of the pants feeling was that everything was fine and if I had ATTO'd the array I'm positive I would have gotten respectable write numbers.

I ended up ditching any sort of RAID and just doing 4 individual drives for the time being until I order a controller. Read and write times are all nearly pegged at around 78,000. Ideally I'd like to get an 8 port like the Highpoint RocketRAID 2320 so I can add the 3 additional 320gb 7200.10's I currently have on to the array, but I may settle for the 4 port 2300 based on price.

[chino182]

can anyone recommend a good raid controller? can i also run a raid 5 with two hard drives?

[gigabyte1024]

can anyone recommend a good raid controller? can i also run a raid 5 with two hard drives?

RAID5 requires a mininum of 3 drives. I'm not trying to be an ass, but do your homework before you try and tackle a RAID setup.