Datastore speed issue - two same drives

[daftu]

Hi,

I've problem with datastore speed in ESXi 5.1. There are two datastores based on local SATA drives. Both drives are the same models - WD1002FAEX 1TB SATA III 64MB.

I've testes both of them and the first one is avg 110MB/s fast, second is avg 80MB/s fast.

Only difference between the datastores is VMFS version, first (faster) is 5.54 (created before upgrading from ESXi 5.0 to 5.1, second is VMFS 5.58 (created after upgrading to 5.1).

Test was made on the same VM (migrated between this two datastores).

Changed cables, changed ports (SATA III, SATA II - no difference).

I suspected drive issue and checked it under different OS (WindowsXP with several disk speed measurement tools) - result was OK, normal speeds.

Only difference is VMFS version, newer = about 30MB/s slower. Is that possible?

Is there any possibility to downgrade (recreate) VMFS to 5.54 instead 5.58?

P.S. Sorry about my english.

[Sreejesh_D]

its unexpected, such a degrade in performance is not natural. Its good to inform VMware by an SR.

>>Is there any possibility to downgrade (recreate) VMFS to 5.54 instead 5.58?

its not possible to downgrade the VMFS version. As far as I know we cant creat a 5.54 version of VMFS from 5.1 host.

If performance is the main concern you can give a try by creating a VMFS3 volume. Its possible form 5.1 host.

[daftu]

I don't think I'm able to open SR because I'm a free version user.

I'll give a try VMFS 3.

[daftu]

Ok, now I'm totally confused.
As You suggested I've recreated the datastore filesystem as VMFS 3 and.... still the same speed issue. So the version of filesystem is not the reason.

Now I have completely no idea about this.

[Sreejesh_D]

it may be a harddisk issue then, please check with the hw verndor.

[daftu]

Already checked. Connected to different host (Windows) and did full tests/benchmarks.

The speed was between 140MB/s (beggining of disk) to 80MB/s (end of disk) which is average 110MB/s. Every test I've seen on the internet gives similar results, so disk is OK.

Maybe it's something with motherboard? Its Intel S1200BTL. Today I upgraded BIOS to newest version but of course without success.

[daftu]

Found the 100% reason of speed issue!

It was the VMFS version - the minor version difference between 5.54 and 5.58.

When I was testing VMFS 3 it was ended with 58 too (version 3.58) so there was still speed problems. I think the point is "58".

Now I downgraded hypervisor from 5.1 to 5.0 (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=103360...) and then recreated datastore with VMFS 5. Now its version 5.54 and is working like a charm with ~110MB/s speed on both drives!

So VMware stuff - there is something wrong with 5.58!

[Sreejesh_D]

thats interesing and thanks for sharing.

[daftu]

Should I report it to VMware in some other way? Like I said - I'm free version users but I think they may be interested in fixing this problem (or not).

[Sreejesh_D]

Try this option, though its for feature request.

[daftu]

What do You mean "this" option? Forget linking sth?

[Sreejesh_D]

oops i missed the URL.

http://www.vmware.com/support/policies/feature.html