I’ve been test driving a script called “mbrscan” for a while now. Today I noticed that this script had already been released a couple of weeks ago. The cool thing about the script is that you can check the alignment of the VM’s filesystem from the outside. The script runs directly on the service console of ESX. NetApp’s Nick Triantos describes it as follows:
There’s a new utility that has been added, called mbrscan. The purpose of mbrscan is to identify whether or not a VM has properly aligned partitions. The script will run successfully under two conditions: a) The VM is powered off b) the VM has VMsnaps. The script will error out if none of the above two conditions are satisfied simply because the VMDK(s) are locked.
This can be very useful to identify possible performance issues within just a matter of seconds. Combine this command with “vmware-cmd” to create and remove snapshots and you’ll have the results for you entire environment within minutes.
Now that you just received your results the real question would be:”How am I going to modify this without destroying the data?”
At this point in time that’s not possible. But I know NetApp is working on a tool called “mbralign”. This tool will make it possible to align the filesystem from outside the VM.
The mbrscan tool is part of the “Unified Host Utilities Kit” which reached version 5. The toolkit isn’t available for everyone, you will need a now.netapp.com/ to be able to download it.
UPDATE: MBRSCAN is a binary not an editable script, and the script version has been floating around for a while now…
vSphere 4.0 Quick Start Guide
Hey Duncan,
Actually Vizioncore just released their vOptimizer Pro product on 1/12 that will allow you to realign the partitions on the 64k block boundary. It does involve powering off the guest OS in order to perform this. vOptimizer will also allow for disk resizing as well.
MBRScan and MBRAlign have been available to netapp customers for some time.
One of our customers has netapp storage and when the consultant was up before xmas he took me through it and showed me how to use it.
Anyone have a direct link to “Unified Host Utilities Kit”?
there’s no direct link… I don’t have a netapp account so i can’t help you out unfortunately…
http://now.netapp.com/NOW/download/software/kit_iscsi/esx/5.0/
You still need a NetApp account, but hey if you are not working with filers, why do you need the tool?
Filer or not, you will still need to align your OS Filesystem. This tool will come in handy.
MBRAlign is not in the download at the moment.(only MBRScan)
Hope they will be releasing that soon.
It does not look like NetApp wishes to be generous and make mbrscan/mbralign available to the general public.
According to the VMWare docs, you do not need to worry about the OS partition alignment if your san luns are aligned properly on the ESX side…
Just to clarify my previous posting since Duncan was in disagreement, I was referring to boot volumes/disks on vmfs luns – apols if there was any confusion!… :\
http://www.vmware.com/pdf/esx3_partition_align.pdf
Page 3 –
Note: Aligning the boot disk in the virtual machine is neither recommended nor required.
Align only the data disks in the virtual machine.
I don’t know why it wouldn’t be recommended. Just to be sure and out of consistency I would do it when creating a Template.