Due to another VMware/NetApp related issue, NetApp support have been looking over our perstat logs from our NetApp filers, the NetApp Engineer spotted and raised some health issues with our VMware LUNS, they are misaligned due to the high numbers of partial write activity, as well as partial reads.
My understanding of LUN/Disk alignment is that one the LUN must be aligned, and for a NetApp LUN the LUN type specified must be VMWARE (when using VMFS), but also the partition OS must be aligned in the virtual machine (vmdk).
I've read a recent document http://www.vmware.com/pdf/esx3_partition_align.pdf, which states
Note: Aligning the boot disk in the virtual machine is neither recommended nor required.
Align only the data disks in the virtual machine.
I assume neither recommended or requried means, it's difficult to do, because when we use P2V we have no control over where the OS partition is put on the vmdk, and when we've installed OSes for our templates, the partition is already created buy the install routine.
The only way for the boot partition to be correctly aligned, is it to be created manually before we install an OS, but this still leaves us with the P2V, unless we shutdown all our VMs, and use partition magic to move the partition 64 bytes!
All our data disks in the virtual machines are stored on LUNs via Snapdrive.
Any one like to comment, or have found a nice utility to move the partiton offset by 64 bytes, although VMware neither recommend or required.