EVA4400 performance issue

[Arman Obosyan]

On EVA4400 with 2 disk enclosure and 300GB 15K FC Drives, all 24 disk is in one Disk Group. I created a Vdisk 100Gb VRAID1, present it to Server 2008 x64 (Qlogiq HBA) and performance test was

sqlio -kW -t3 -s60 -b4
sqlio v1.5.SG
3 threads writing for 60 secs to file testfile.dat using 4KB IOs over 256KB stripes with 64 IOs per run initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec: 9488.56
MBs/sec: 37.06

Then I create a disk 350Gb, RAID1 on and present it to the same host, speed is twice different!
D:\SQLIO>sqlio -kW -t3 -s60 -b4
sqlio v1.5.SG
3 threads writing for 60 secs to file testfile.dat using 4KB IOs over 256KB stripes with 64 IOs per run initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec: 4675.58
MBs/sec: 18.26

Why its happens? VDisk from same storage in the same Disk Group has different performance?

[Jan Soska]

Hello,
really stange, as you use the same disk/raid it shoudnt be different.
Try other parameters/ benchmarks?

Jan

[chris huys_4]

Hi,

Why do a IOtest which adds software striping, to a EVA diskarray that allready, afaik, does hardware striping of all IO by default ? (and software striping over hardware striping normally worsens the performance) Remove the software striping parameter and see what the results are then.

Greetz,
Chris

[Arman Obosyan]

Jan Soska,
Yes for example test it 64k size (sqlio -kW -t3 -s60 -b64)
And test results are same on LUNs

100Gb Raid1 VDISK
L:\SQLIO>sqlio -kW -t3 -s60 -b64
sqlio v1.5.SG
3 threads writing for 60 secs to file testfile.dat using 64KB IOs over 4096KB stripes with 64 IOs
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec: 3540.73
MBs/sec: 221.29


350Gb Raid1 VDISK
D:\SQLIO>sqlio -kW -t3 -s60 -b64
sqlio v1.5.SG
3 threads writing for 60 secs to file testfile.dat using 64KB IOs over 4096KB stripes with 64 IOs
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec: 3744.12
MBs/sec: 234.00


But why is so different wane I use 4k size? May be its depends on vdisk size?

Chris Huys,
Remove the software striping parameter? Where or how? I'm not using any stripe

[Jan Soska]

hello,
I do not know sqlio software, so I can not help with stripping options.

Regarding block size - different block size results in very different results. Smallar block usually produce small r/w perf - as they require more IOs. Each drive is cabable only of limited amounth of IO - in case of 15K FC drives let say 170 IOps per drive. If you use bigger block - you need less IO and get better w/r performance.
But remember - this works only in case of large block used by application - which is usually not true (maybe in video editing it is ok). So you have to try block size used in your app, or tune the application how it works with different block size.
If I am not wrong, EVA's use 128K block natively.

Jan

[Arman Obosyan]

Disk are prepared for SQL, that why I decide to use sqlio, is Microsoft tool, SQLIO Disk Subsystem Benchmark Tool
http://www.microsoft.com/downloads/en/details.aspx?familyid=9A8B005B-84E4-4F24-8D65-CB53442D9E19&displaylang=en

[chris huys_4]

Hi,

> D:\SQLIO>sqlio -kW -t3 -s60 -b4
> sqlio v1.5.SG
> 3 threads writing for 60 secs to file
> testfile.dat using 4KB IOs "over 256KB
> stripes" with 64 IOs per run initialization
> done

The "over 256KB stripes" suggest the sqlio tool is emulating striping with the "given sqlio command options"..

While f.e. from the following url :
http://communities.vmware.com/thread/90464

, the following sqlio command doesnt do "striping"..

C:\Program Files\SQLIO>"C:\Program Files\SQLIO\sqlio.exe" -frandom -i1
sqlio v1.5.SG
1 thread reading for 30 secs from file testfile.dat
using 2KB random IOs
using current size: 8 MB for file: testfile.dat
initialization done

Also I suppose, that the eva4400 should be giving results, comparable, with the following sites results for a eva6100..

http://blogs.mssqltips.com/blogs/chadboyd/archive/2008/03/16/ssd-and-sql-sqlio-performance.aspx

Greetz,
Chris

[Jan Soska]

Hello, another good testing software is HF Tune Pro, trial version works for 15 days, you can specify block size etc...

Jan

[Arman Obosyan]

thanks to all.