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VSA disk planning

Honored Contributor

VSA disk planning

I've been running into some performance issues with my software VSA nodes running on hyper-v.  The systems are under-spec for spindles as is so I want to make sure i"m not eating up needless IOs through my configuraion between disk/raid/NTFS/iscsi/NTFS stripe/block sizes.


Here is the setup:

Disk Sector Size:  512b

Hardware Raid5 stripe:  128k

NTFS cluster size on Hyper-V computer: 64k

HP VSA:   ??????  I don't know what it is

iSCSI target LUN cluster size:  64k  (the cluster size for my hyper-v CSV LUNs)

.VHD files on CSV drives:  mixed between 4k clusters for OS drives and 64k for storage/app drives.


I was talking with the raid card vendor and they suggested 64k for their stripe size works best for their system. 


I feel like cluster/stripe size is something that is rarely talked about and thought I woudl poll the group to see what others are doing and if there are any suggestions.  I'm tempted to try using 64k throughout or do 64k hardware and 4k for the rest, but I"m worried about alignment issues.  I was told by the raid card mfg that it isn't an issue for the hardware level.





Frequent Advisor

Re: VSA disk planning

From what I've been told by HP support, which must be taken with a grain of salt, the P4000 stripe size is 64k.

I would strive to use 64k on the hardware side, with that in mind. 

For the guest OS side, I use 64k for servers that are doing large IO, and I don't worry about it for the others. 


Honored Contributor

Re: VSA disk planning

That is what I've been thinking lately.  my concern is with allignment... if the sizes are the same and they aren't alligned then that means you are doubling the IO load 100% of the time.

Occasional Advisor

Re: VSA disk planning



Just wondering if you had any perfromance results during your stripe size testing? Did you go for 64K on the raid card in the end?



Honored Contributor

Re: VSA disk planning

I was looking for this thread to update :)


I ended up going with 256k stripes on my raid card because it seemed to work the best with my LSI raid cards.  I also directly presented the drives to the VM so I didnt' have to deal with figuring out the best NTFS cluster size. and I don't have to worry about extra free space on the drive that houses the vhd.



Regular Advisor

Re: VSA disk planning

I am under the impression that 2008 / R2 type OS's align their own sectors during the format. I was under the impression that it was clever enough to work it out during setup.. May be wrong however, this is just what I remember from when i researched it quite a while ago...

David Tocker
Prakash Singh_1
Esteemed Contributor

Re: VSA disk planning

You can refer to the HP Guided troubleshooting tree for VSA planning and for some issues on the left hand networks


Select option VSA planning and installation and getting started with the Centralized Management Console (CMC)



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Regular Advisor

Re: VSA disk planning

If you use the CLIQ and run the getvolumeinfo command, the reported block size for the SANiQ volumes is 1024k. My system is in VMware, so I'm not sure if that changes using Hyper V.