What size files is VMWare reading/writing? 64k or 256k Stripe Size for RAID ARRAY?

[TahoeTech]

I am setting up a 2Tb RAID 10 array for use as Datastore with VMWare... I am going to be creating a VM that needs a 1.5TB hardrive. So when I format the Datastore as VMFS I will need to choose the 2TB Max File size option, that formats the drive with 8MB block size...

But before I can get that far, I need to create/build the RAID Array and I usually do 64K stripe size, but I don't know what size files VMWare is reading/writing?

So I ask you all, should I use a 64K or 256K stripe size when building the initial ARRAY.

ARRAY Details: RAID 10 using 8 x 500GB drives yielding ~ 1.83TB

Thanks for any help!

[RParker]

Doesn't matter, VMFS is formatted on the LUN. So for this part you don't need to worry how to make the underlying volume, it won't make a difference.

If however you are making an NFS mount, then I would use 64K, otherwise LUNS are handled by VMFS proprietary format.

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[TahoeTech]

So the initial stripe size that I set when I create the RAID ARRAY on the RAID controller has NO effect on the performance once I format from inside VIC using the VMFS?

[RParker]

Right. The Volume is RAW. The LUN is just a large chunk. VMFS comes in and formats the LUN, Volume doesn't matter.

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[Rumple]

Ps - i would probably make that LUN 1.9TB in size vs 2TB exactly. I belive you will have problems with the LUN being exactly the same as the MAX LUN size. Could probably try for 1.95TB....

[darkfriend]

I wouldn't say that the initial stripe size doesn't effect performance. Even a raw RAID volume has read/write performance. Different stripe sizes will effect controller performance in read vs write speeds, regardless of the file system placed upon it. I've seen controllers set to 256k that increase read speed and sacrifice write speed, but when set to 64k they will balance out...depends on the controller. But, ultimately, you're beyond stripe size assignment at this stage in the game. Testing the RAID controller performance at different stripe sizes is more for critical testing purposes at the bleeding edge of performance. I would stick with 64k or 128k, unless you have some hands on testing experience with that particular RAID controller. But whatever you assign will likely impose no noticeable difference in this application.