VMware Solutions Discussions

Are MBR Tools needed with ESXi?


Good afternoon,

We are deploying remote offices with FAS2020 NetApp and two vSphere 4.1 (ESXi). As we are using ESXi instead of ESX (Recommended directly by VMWare), we don't know if it's necessary to install MBR Tools and how to do it, as they only works in ESX hosts.

Can anyone help me please?

Thank you so much, best regards.


Re: Are MBR Tools needed with ESXi?



I think you might be asking 2 different things. With ESXi you do not install the Host Utilities Kit (HUK) since it will not work with ESXi. Instead you use the VSC which is installed with vCenter to configure the ESXi hosts (HBA settings, time out values ect.)

MBRalign is used to align the guest VM file system. You are correct that MBRalign does not work with ESXi so you have to align the VMs (if they require it!) using a full version of ESX or a 3rd party tool that is compatiable with ESXi (Quest, Paragon ect).

If your templates are aligned though evey VM deployed from the template will be aligned and it is a non issue.

We also have some solutions for ESXi and alignment in the works coming soon!


Re: Are MBR Tools needed with ESXi?


Ok Keitha I understand, but how can I be sure template is aligned, or how can I align it without an ESX host? All of our hosts are ESXi.

Thank you so much, regards

Re: Are MBR Tools needed with ESXi?


There are a couple of ways to check the starting offset manually. Details here http://media.netapp.com/documents/tr-3747.pdf

Basically you want an offset that is a factor of 4K

View solution in original post

Re: Are MBR Tools needed with ESXi?


Oh ok, thank you so much Keitha for your answer, my question is fully answered.

Goodbye, best regards 😉

Re: Are MBR Tools needed with ESXi?


Until something more permanent comes along, what I use to make sure that legacy or new templates are fully aligned is a mixture of the following:

  • New Templates or VMs - Boot the VM using a PE environment (WinPE, Linux etc) before installing the OS, I then create the partition using tools like DiskPark or GParted ensuring that the starting offset is a factor of 4 (DiskPart is something like partition create primary align=32, I can't remember exactly sorry).
  • Old Templates or P2V VMs etc - Build a Linux box (I usually use Ubuntu) if you are using NFS datastores this is quite easy as you can just export and mount them to this Linux box, install the MBRTools (basically extract and copy them to somewhere in the path - /usr/sbin for example) and then run them against the VMDK files in the NFS mounts. If you are using LUNs then its a little more complicated as you would need an additional server with a HBA or use iSCSI. Don't forget that the VM's need to be powered off before you start the scan or re-alignment process.

Also it's worth noting that this only affects operating systems prior to 2008/Vista as the correct starting offset is now the default.

Are MBR Tools needed with ESXi?


Hi keitha,

I'd like to ask you related questions. If possible, could you provide us answers?

  1. According to the document, tr-3747.pdf, Windows2008R2 and RHEL6 do not need to reconfigure alignment. Are there any lists which show what OS, such as RHEL5.6, need to be aligned?
  2. In the same document, it is written, "For Citrix XenServer NFS SR, this tool (mbrtool) can be run from domain 0 (dom0)." In this case, can we install ESX host utilities in dom0 and use mbrtool to .img files (Actually I aim to use mbrtool on OracleVM)?

Since my system will be build using ESXi (and OracleVM), I look forward to seeing solutions for ESXi and alignment!



Earn Rewards for Your Review!
GPI Review Banner
All Community Forums