I'm trying to grasp the entire subject of partiton alignment as it relates to both the filesystem (NTFS, FFS, etc.) and the underlying storage devices.
My question is: are there questions that should be asked of your hardware vendor (and if so, what questions *should* be asked) to be SURE that any new VMs are properly aligned and/or that any existing VMs are properly aligned.
Here's what I *think* is correct:
Relative to partition alignment for SAS and/or SATA drives (SSDs are a different topic altogether), there are a few things to consider/confirm before you can be sure your partitions (VMs) are correctly aligned:
1.) The VM filesystem (whether it's NTFS in Windows machines or UFS, FFS, etc. for a *nix machine) must be in alignment relative to the underlying VMFS
2.) One of the keys to proper partition alignment is to confirm that partition starting offset is an even, integer value of 512.
When creating NEW VMs, your partition starting offset (whether they're Windows or *nix) must be an even, integer value of 512. For existing machines, if the partition starting offset is not an even, integer value of 512...you have a machine that is obviously out of (partition) alignment that should be corrected (IF you want to optimze performance)
3.) The VMFS must be in alignment relative to the underlying storage appliance.
If these are true, then what (if anything) should I be asking my storage vendor as it relates to correct partiton alignment??? How does the use of RAID and multiple drives factor into proper partition alignment?
P.S. If you know of any additional documentation that you think might help claifiy this topic...I'd love to know about it.
Thank you,
Ed
