topic Misaligned VM on ESXi in VMware Solutions Discussions

Misaligned VM on ESXi

adamgross — Thu, 05 Jun 2025 06:51:19 GMT

Since mbrscan/mbralign don't work on ESXi, what alternatives are available? The first thought that popped into my head was to copy the -flat.vmdk to another linux host, align it and copy it back but that will be extremely time consuming. Are there any other in-place tools that operate similarly to the way mbralign does within ESX? Thanks.

Misaligned VM on ESXi

scottgelb — Fri, 01 Jul 2011 20:34:49 GMT

Without an ESX service console for this you need to run on Linux like you mentioned... If NFS, then you don't have to copy to Linux first, but it sounds like you are using VMFS since you are copying the file. Paragon is also an interesting tool and works inside the windows VM itself to realign within the LUN (needs some free space). One of our astute customers told us about it and we tested internally and in our own I.T. group and it worked as advertised. If a C: drive it reboots and other drives go offline but the vm stays up and it aligns without copying to a new vmdk. It does need some free space in the vmdk though.

Misaligned VM on ESXi

adamgross — Tue, 05 Jul 2011 13:28:49 GMT

I think I'm a bit behind the times with NFS, so permit me a potentially dumb question. To get this done without copying files A->B and then B->A, all I need to do is:

Add my linux host to the read-write hosts list on the filer

Mount the datastore in my linux host

Shutdown the guest

Run mbralign

Dismount the datastore in linux

Power up the guest

Done?

Thanks again Scott.

Misaligned VM on ESXi

scottgelb — Tue, 05 Jul 2011 14:24:02 GMT

If an nfs datastore that will work... might want root access too for the linux host. make sure you have enough room for a full copy of the -flat.vmdk file and also to clean up -mbralign-backup files after you confirm all is working ok.