Alignment Question

[heybuzzz]

Two questions...

If my VMFS is aligned at 128 (I checked my LUNs running fdisk -lu) and my Windows guest files system c:\ is aligned at KB 64 what do I need my SAN admin to check on there side (EMC Clarion)?

Also, if I add a D:\ virtual disk to my aligned C:\ do I need to do anything special to the new added disk or is it aligned because the C:\ is? I only ask because my c:\ is aligned using v Optimizer Pro and my D:\ read "not aligned".

Thanks

[mittim12]

If you added a second VMDK drive to an exisiting VM you would need to align that drive as well.

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[vmroyale]

Hello.

If my VMFS is aligned at 128 (I checked my LUNs running fdisk -lu) and my Windows guest files system c:\ is aligned at KB 64 what do I need my SAN admin to check on there side (EMC Clarion)?

"in the EMC CLARiiON Best Practices for Fibre Channel Storage guide available at EMC Powerlink, EMC recommends a starting block of 128 to align the partition to the 64KB boundary." - taken from the "[Recommendations for Aligning VMFS Partitions|http://www.vmware.com/pdf/esx3_partition_align.pdf]" performance study. There is also good information in this document about guest alignment.

Good Luck!

[heybuzzz]

Ok, so after I add the new HD and go into the OS disk mang util what would be the next steps after intialization? I don't see any mention of it here http://www.vmware.com/pdf/esx3_partition_align.pdf

Thanks

[vmroyale]

Using the instructions on pp.3-4 of that document, you will use a command line and the diskpart utility. Don't use the GUI for the alignment, but it is fine for the formatting. This is true in pre-2008 versions of Windows. In 2008, you can use the GUI as it will align properly.

[heybuzzz]

Man... So if my c:\ is aligned on my template and I then create a new VM from say template I need to manually aligh every new partition I add? That's if I'm creating 2003 R2 VM... Thanks

[vmroyale]

Man... So if my c:\ is aligned on my template and I then create a new VM from say template I need to manually aligh every new partition I add? That's if I'm creating 2003 R2 VM.

Yes, unfortunately that is correct. And to make matters worse, the data partitions are the ones that will benefit most from the alignment.

[heybuzzz]

I've also read and tried to use the Windows defrag tool to defrag once the VM is aligned and it fails. So basically, if I alighn my VM's I need to purchase a third party tool to defrag for now on...?

Thanks

[AndreTheGiant]

Have a look also at this document:

Andre

[heybuzzz]

Thanks. I've read the article once before but after the re-read noticed this...

http://www.vmware.com/pdf/esx3_partition_align.pdf

Note: Aligning the boot disk in the virtual machine is neither recommended nor required.

Align only the data disks in the virtual machine.

So is that saying that my C:\ with my server 2003 OS installed is not recommended to have a 64k alignment? Just align my data drive.... I've always thought best practice was to align both but knew aligning my data drive was most important. hmmm

[AndreTheGiant · Accepted solution]

The document is old.

On Windows OS after Vista partition are already aligned.

On other, there no really need to align also the OS disk.

Andre

[heybuzzz]

I've already aligned my 2003 templates and will align any new disk/s added after I create the VM from those templates, but what about the built in defrag? I've tried it a few times and it fails. Since the built in defrag doesn't like the new alignment does that mean I need to find another option?

[AndreTheGiant]

I never align a C: volume on Windows 2003 Server, but for the others disk (if you align them BEFORE the formatting), I've see no issue with defrag or other tools.

Andre

[heybuzzz]

Thanks for your suggestions... I will test that now.