FAS and V-Series Storage Systems Discussions

ESXI Remote console & Disk Alignment

Hi Guys and Gals,

we are currently implementing our fist Netapp Vseries solution and i'm kinda a noob. So Sorry if i seem a bit thick.

I have presented some disk stores to our ESX environment and now we are looking to migrate some of oour VM's to this store. We currently have an ESXI cluster running accross our DC's. I have had a look at the disk components of our VM's and they appear to be out of alignment. Our environment is win2k3 and 2k8. The 2k8 VM's should be fine but the 2k3 VM's need to be aligned. I have downloaded the ESX Host Utilities 5.1 as netapp claim there are problems with 5.2.

Can anyone point me in the right direction of how i run mbralign from remote to a vmdk file?

Thanks in Advance for all you help.


Re: ESXI Remote console & Disk Alignment

Are you using NFS datastores? Or block level?

If NFS you can run the MBR align tool from any linux helper VM VM fairly easily

There is a nice writeup here


Re: ESXI Remote console & Disk Alignment


Thanks for the quick reply to my post. We are using block level. Your right it's a nice write up on mbralign and mbrscan.

Unfortunitaly it does not solve my problem.

Re: ESXI Remote console & Disk Alignment

Hi Scott,

This is covered in the install and admin guide for VSC 2.01


Also covered in the ESX Host Utilities Kit install and admin guide.


As you are using ESXI I think you should be referrring to the VSC guide rather than host utils.



P.S. Make sure you have a backup before you run it.

Re: ESXI Remote console & Disk Alignment

Hi Dominicb

Thanks for the assistance. My question is still how do i run the mbrtools on ESXI when the VM has to be shut down to run the tools?

Checking VMDK partition alignment with mbrscan
You can use the mbrscan tool included with Virtual Storage Console to check VMDK partition

About this task
The mbrscan tool is effective on -flat.vmdk and fixed .vhd files that are partitioned using a master
boot record (MBR) partition table.
1. Shut down the virtual machine.
If you do not want to shut down the VM, take either a Data ONTAP Snapshot copy of the volume
containing the Datastore LUN or NFS Datastore, or take a VMware snapshot of the VM in
question, and then run mbrscan against the copy.
2. On the ESX host console, change to the directory where mbrscan is installed.
3. Enter the following command on the ESX host console:
./mbrscan { --all | filename }
The --all option scans all -flat.vmdk files.
filename specifies the name of a single file to scan.
The command displays whether the VMDK partition is correctly aligned.

Can this be run from the Virtual Center Server? Maybe i am getting confused here. "Most Likelly"

Re: ESXI Remote console & Disk Alignment

The mbrscan and mbralign tools need to be installed on the service console of an ESX machine (not esxi as it does not have a service console) or a helper VM if it can access the storage.

As you are running block level storage a helper VM is not useful to you as it cannot access your storage (Even if you passed it the LUN's it would not know what to do with VMFS)

Looking at other threads like this http://communities.vmware.com/thread/263820;jsessionid=95EB63CD3D05C808AAE0B10DB5686502?tstart=0 some people are putting in an ESX box temporarily and attaching it to their storage to perform the alignment work.

Other than that I have not been able to find a work around for block level storage and ESXI other than a temporary full blown ESX installation.

What you COULD do if your licensed for NFS on your filer, even if you don’t want to use it for your production storage protocol is make a temporary NFS volume, storage vmotion the target VM’s over to it (thereby making it accessible to a helper VM) align it and storage vmotion it back.

Other than that I am not sure if any of the other 3rd party alignment tools out there can interface with an ESXI box.

Re: ESXI Remote console & Disk Alignment

"shutdown the virtual machine" my understanding is to shutdown the vm you are going to run the mbr tool against, not the vm that virtual center is running on.

Is that what you mean?

You can also check VM alignment from a Windows 2003 host without shutting it down by looking at:

Start -> All Programs -> Accessories -> System Tools -> System Information

Then expand Components section then expand Storage section and select "Disks"

Look in the list of settings in right pane for Partition Starting Offset. If this number is divisible by 4096 then you are aligned. If it is not then you are misaligned.

More details in here, page 80:


Re: ESXI Remote console & Disk Alignment

Thanks Again Doninicb

I have already verified that the VM in question is out of sink. My issue is that the Environment is ESXI, You can't install the ESX host utilitieson ESXI so how can i run the mdrscan tool?

Re: ESXI Remote console & Disk Alignment

Hi Scott,

Referencig this doco:


Best Practices for File System Alignment in Virtual Environments

In order to leverage the NetApp mbralign tool for correcting the file system partition alignment for misaligned VMs hosted on ESXi hosts, NetApp recommends leveraging a standby VMware ESX host and using a supported version of the mbralign tool to fix the VM alignment issues. This standby VMware ESX host should have access to the NFS/VMFS datastores hosting the misaligned VMs. Also, it is not required that this ESX host be part of the HA/DRS cluster hosting production VMs.

I think you will have to install a temp ESX host to use the mbralign tool.



Re: ESXI Remote console & Disk Alignment

Sorry Jeredarassier,

I missed your post in haste to try and solve this problem. It looks like you have answered the question. I don't seem to be able to find another way of making this work. I have searched the net for majority of the day looking for a solution here. We might just have to bite the bullet and connect a full blown ESX os to our environment