fschaller
Contributor
Contributor

ESX 3.5 Disk Performance on Perc 6/i

Hello everybody,

I have a ESX test installation (first time I use an ESX Server) with following configuration:

2 x Quad Core L5335

Perc 6/i

6 x SAS 146 GB with 10k (RAID 6, Write Through, Read Ahead Deactivated, 64k Stripe Size)

I use the local disk for the datastore.

Now I get more or less 15000 KBps Write Performance, measered with another Tool between 12MB/s - 16MB/s.

Is this ok? Do I have a RAID configuration error. Now I can change anything (it's just a Test-System). In a month I'm messed up ;-).

Thanks for your help!

Regards Frederik

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2 Replies
fschaller
Contributor
Contributor

Ok, I'm going to reply myself ;-).

I activated the Raid Controller Write Cache.

Now I have a disk write performance between 45MB/s and 65MB/s, depending on the file size.

That looks reasonable to me - what do you think?

My second question is: Is the write cache (assuming your controller has a battery) really a data security issue?

Thanks for your help, Frederik

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Ken_Cline
Champion
Champion

Ok, I'm going to reply myself Smiley Wink.

Better be careful...you know what they say about answering yourself Smiley Wink

I activated the Raid Controller Write Cache.

Now I have a disk write performance between 45MB/s and 65MB/s, depending on the file size.

That looks reasonable to me - what do you think?

Not bad...

My second question is: Is the write cache (assuming your controller has a battery) really a data security issue?

Potentially. The issue is that, with the BBWC enabled, the controller's cache will retain potentially sensitive information in the cache. If someone can gain physical access to the system, they could - with the right set of tools - extract that information. Now, when you consider that - if they can get to the controller, they can get to the drives - then the exposure seems trivial...just make sure you purge the cache before you discard the controller (i.e. if it needs to be returned for service, when it reaches end of life, etc.)

Ken Cline

Technical Director, Virtualization

Wells Landers

VMware Communities User Moderator

Ken Cline VMware vExpert 2009 VMware Communities User Moderator Blogging at: http://KensVirtualReality.wordpress.com/
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