Low RAID 5 Write Performance on P5Q Deluxe

[bnlitin]

I have just setup a RAID 5 partition on a Asus P5Q Deluxe with Q9450 @ 2.66 GHz.
I am using 6 WD10EACS drives (6 x 1TB) in a RAID-5 partition, using the onboard Intel RAID controller (ICH10R).

I am concerned about RAID 5 write performance and would like some input from others.

1. The RAID 5 is still showing as "initializing" after 10+ hours. How long does this initialization usually take?
2. When writing files from another PC, I normally see 40 MBytes/sec of write performance over a 1 Gbps link. I am seeing about 8-12 MB/sec to the RAID partition. This seems a bit low. Is this due to the initialization still going on or due to the Intel RAID5 implementation?
3. If anyone else has setup RAID5 on P5Q Deluxe, can you post your performance numbers and setup info?

I set the stripe size to 64KB. I will be using the RAID5 partition to store movies. What size stripe is recommended for media?

Thanks for any suggestions.

 

[SunnyD]

If you're that serious about it, shouldn't you be using a real RAID controller?

 

[VirtualLarry]

If you haven't yet, pop on over to www.storagereview.com . There is a thread there on optimizing RAID5 performance for onboard chipsets.

 

[xxsk8er101xx]

Sounds like you don't know what you're doing.

You got x6 1TB drives. It's going to take a day or two to stripe that.

You're raid is still building so it's going to be slow until the raid build is done.

Striping size should be set based on what you're storing. If you're storing 30k jpeg files you will probably want 16k striping size. Since you're storing 1gb+ file sizes the largest striping size is optimal.

You may want to get a server RAID adapter from LSI. A bit expensive but if you got the money this is the way to go. LSI LSI00142 x8 lane

Other than that you'll have to get a server board with a server chipset and a xeon processor to get great drive performance. SAS drives would give you excellent drive performance.

Originally posted by: bnlitin
I have just setup a RAID 5 partition on a Asus P5Q Deluxe with Q9450 @ 2.66 GHz.
I am using 6 WD10EACS drives (6 x 1TB) in a RAID-5 partition, using the onboard Intel RAID controller (ICH10R).

I am concerned about RAID 5 write performance and would like some input from others.

1. The RAID 5 is still showing as "initializing" after 10+ hours. How long does this initialization usually take?
2. When writing files from another PC, I normally see 40 MBytes/sec of write performance over a 1 Gbps link. I am seeing about 8-12 MB/sec to the RAID partition. This seems a bit low. Is this due to the initialization still going on or due to the Intel RAID5 implementation?
3. If anyone else has setup RAID5 on P5Q Deluxe, can you post your performance numbers and setup info?

I set the stripe size to 64KB. I will be using the RAID5 partition to store movies. What size stripe is recommended for media?

Thanks for any suggestions.

 

[Madwand1]

Originally posted by: xxsk8er101xx
Striping size should be set based on what you're storing. If you're storing 30k jpeg files you will probably want 16k striping size. Since you're storing 1gb+ file sizes the largest striping size is optimal.

No, stripe size is not related to file size, and the largest stripe size is not likely to be optimal. The only way to determine the optimal stripe size is to test it -- different implementations have different quirks.

 

[Madwand1]

Originally posted by: bnlitin
I am using 6 WD10EACS drives (6 x 1TB) in a RAID-5 partition, using the onboard Intel RAID controller (ICH10R).

I am concerned about RAID 5 write performance and would like some input from others.

Did you turn on write caching in the RAID utility? It's critical for write performance.

If that doesn't do it, then I suggest, unfortunately, trying a smaller stripe and/or a smaller number of drives. To speed up this process, I suggest making a small Matrix array for testing purposes. To test performance quickly, I suggest using ATTO 256 MB with "Direct I/O" "Neither". This is not the best test, so don't use it for fine tuning or worry about a few 10's of MB/s here or there, just use it for ballpark performance indicators -- it's pretty much very bad vs. pretty good in such cases. If you really want to "fine tune" it, I suggest learning to use IOMeter. But that's likely to be overkill here, as you should be bottlenecked at the OS and network level, not RAID.

 

[bnlitin]

Everyone, thanks for your help!

The RAID 5 array completed initialiazation after 24+ hours. Using Sandra SiSoft, I am getting 150-180 Mbps read performance and 40-60 Mbps write performance, which is fairly reasonable for an on-board RAID controller. I am using a stripe size of 64K, but have not tried any other sizes. it looks like by initial low array performance was due to the Array undergoing initialization. I didn't realize it took so long.

 

[SunnyD]

Originally posted by: bnlitin
Everyone, thanks for your help!

The RAID 5 array completed initialiazation after 24+ hours. Using Sandra SiSoft, I am getting 150-180 Mbps read performance and 40-60 Mbps write performance, which is fairly reasonable for an on-board RAID controller. I am using a stripe size of 64K, but have not tried any other sizes. it looks like by initial low array performance was due to the Array undergoing initialization. I didn't realize it took so long.

I'm kindof curious - why kind of CPU utilization are you getting when you're doing heavy disk IO?

 

[bnlitin]

SunnyD -

CPU utilization for RAID-5 seems very low, but I have not run any benchmarks.

 

[Madwand1]

Originally posted by: bnlitin
The RAID 5 array completed initialiazation after 24+ hours. Using Sandra SiSoft, I am getting 150-180 Mbps read performance and 40-60 Mbps write performance, which is fairly reasonable for an on-board RAID controller.

No, 60 MB/s is still low for sequential writes -- it should be closer to read performance.

E.g., with drives which are dated now and probably slower than yours:

http://i89.photobucket.com/alb...-3vs4-wb-on-vs-off.png

 

[postmortemIA]

RAID5 has slow small writes, known downside for it.

 

[Madwand1]

Here are some measurements done using ATTO, with sequential access sizes going down to 4 KiB.

4 drive Intel RAID 5 (ICH8DO), 64 KiB stripe size.

http://i89.photobucket.com/alb...ir5-4-64-4-Vista64.png

 

[xena10003]

Make sure all your drives are set for SATA-II (300) operation. This should be detectable by the Intel RAID software. Also be careful of bad drives; you may want to run a diagnostic on each of your tera's separately. We roll out Dell Optiplex 755 units at work all the time with 250x2 mirror RAID and sometimes one of the drives will be bad and cause the RAID mirror to build very slowly or to constantly repair.

 

[lopri]

Originally posted by: bnlitin

2. When writing files from another PC, I normally see 40 MBytes/sec of write performance over a 1 Gbps link. I am seeing about 8-12 MB/sec to the RAID partition. This seems a bit low. Is this due to the initialization still going on or due to the Intel RAID5 implementation?

Is the slow performance experienced only over the network? If so, what is your OS?

If you're using Vista, you may want to check this out.

http://www.anandtech.com/syste...howdoc.aspx?i=3233&p=2