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Horrible I/O performance on ML350 when compared to ML110 and ML115

Guillermo Avalos
Occasional Advisor

Horrible I/O performance on ML350 when compared to ML110 and ML115

Hey guys,

This morning I decided to run some test to benchmark the I/O performance on our servers, since it's saturday morning and there's no one here.

The first test was with the AJA System Test, which is not exactly a server-grade random read/write test, but running the same test on all server would give me a fair comparison, right? FYI: the test writes a single 256MB file.

So, here's the breadown:

ML350 G5 RAID5 4x SAS SFF 10k 146GB
Quad-Core Intel Xeon 2.5GHz, 6GB RAM
HP E200i 512MB BWC SAS RAID
Windows Server 2003 R2

Write: 17MB/s
Read: 175MB/s

ML110 G5 RAID1 2x SATA 7.2k 1TB
Dual-Core Intel Pentium 1.8GHz, 3GB RAM
Intel 3200 Integrated SATA RAID
Windows Server 2008 Standard

Write: 38MB/s
Read: 86MB/s

ML115 G5 RAID10 4x SATA 7.2k 500GB
Dual-Core AMD Opteron 2.2GHz, 3GB RAM
Nvidia MCP55S Integrated SATA RAID
Windows Server 2008 Standard

Write: 125MB/s
Read: 126MB/s

ML150 G2 JBOD 2x SATA 7.2k 250GB
Intel Xeon 3.2GHz, 1GB RAM
Windows Server 2003 Small Business Server

Write: 43MB/s
Read: 60MB/s

This is pretty much standard I/O performance for SATA drives, either single or striped.
However, the shocker came with the ML350 G5, the most powerful server of the bunch.
It's running a 4-drive RAID5 stripe of 10k SAS drives, wich I assume would obliterate a 2x RAID0 stripe of slower SATA drives. I could ony get 17MB/s writes. I believe this is due to the nature of RAID5 (having to calculate parity for each block) but come on! 17MB/s?!? This is a 256MB file striped into 64KB blocks, so there's quite a lot of parity to calculate. Maybe the performance would be higher using smaller files.

Read performance is quite acceptable (175MB/s) but I was hoping to break 230MB/s with 4 drives. Either the E200i controller sucks, or RAID5 sucks completely altogether.

Should I switch to RAID10 instead? I will loose a couple of GB of usable space, but hopefully I'll get faster writes.

It's so funny that I get faster write performance on a $500 ML115 with integrated Nvidia SATA RAID controller than on a $2500 ML350 with Enterprise grade SAS drives and dedicated RAID controller. It's actually kind of frustrating.

To keep this in perspective, this are the results for my MBP:

MacBook Pro (late 2008) 1x SATA 5k 320GB
Dual-Core Intel Core 2 Duo 2.53GHz, 4GB RAM
Mac OS X 10.5.7

Write: 53MB/s
Read: 58MB/s
3 REPLIES
Guillermo Avalos
Occasional Advisor

Re: Horrible I/O performance on ML350 when compared to ML110 and ML115

using the CLI ACU doesn't seem to do anything. I disabled the write cache, enabled it back again, modified the cache ratio and all... it still tops at 17MB/s with the AJA System Test.

controller slot=0 modify drivewritecache=enable
controller slot=0 modify cacheratio=25/75

I also run ATTO Disk Benchmar, this is what I got:



Well, using the CLI ACU doesn't seem to do anything. I diasabled the write cache, enabled it back again, modified the cache ratio and all... it still tops at 17MB/s with the AJA System Test.

controller slot=0 modify drivewritecache=enable
controller slot=0 modify cacheratio=25/75

I also run ATTO Disk Benchmark to compare it with your results, this is what I got:

ML350 G5 E200i with 4 10k SAS drives in RAID 5 (50% write/50% read cache ratio)
http://www.quicksnapper.com/Guille779/image/4x-sas-10k-raid-5-e200i-50-50/

ML350 G5 E200i with 4 10k SAS drives in RAID 5 (75% write/25% read cache ratio)
http://www.quicksnapper.com/Guille779/image/4x-sas-10k-raid-5-e200i-25-75

ML115 G5 with 4 7.2k SATA drives in RAID 10
http://www.quicksnapper.com/Guille779/image/4x-sata-7-2k-raid-10/

ATTO reports higher reads, almost 300MB/s, and somehow faster writes (about 25MB/s) but still nowhere near as fast as it should be.
Yuri Holowatsky
Occasional Visitor

Re: Horrible I/O performance on ML350 when compared to ML110 and ML115

I don't know if you are still fighting this battle - but try this:

Enable the on-disk cache and disable the array accelerator. Be aware that your box better be hooked up to a reliable UPS! Run your tests again.

I did the same testing you did, except my config was a RAID10:

With array accelerator on and on-drive cache off: reads ~190MB/s, writes ~30MB/s
With array accelerator off and on-drive cache on: reads ~190MB/s, writes ~175MB/s

Good luck and let me know. I suspect that HP has a problem with their on-card caching. Sure it's safe and back-up by battery - but boy-oh-boy does the write performance suck!

Anyone more knowledgeable than me is welcome to chime in. I'd like to hear some solutions to this that don't put my data at risk and give me "better than a laptop drive" write performance.
Guillermo Avalos
Occasional Advisor

Re: Horrible I/O performance on ML350 when compared to ML110 and ML115

Hi!

I've moved from a 4-drive RAID 5 setup to a 6-drive RAID 10 configuration. Although the performance has increased (78MB/s writes at 128k, 68MB/s at 8192k), I still believe it can do way better.

I'm going to perform those changes and see what happens.