Fixing storage misalignment – Part 3

Offline disk alignment using NetApp toll called mbralignment tool

In most cases offline alignment would be performed on old Linux or Solaris versions.

  • make sure VM is powered of and has no snapshots
  • SSH to ESX(i) box
  • change patch to datastore where misaligned virtual machine is located
  • alignment tools are located on /opt/ontap/santools/
  • do scan of the virtual machine VMDK FLAT file to make sure is misaligned, as you can see, first disk is not aligned. Offset is 32256 /4096 = 7.875 – as you may already know, offset should be dividable by 4096

  • Time to align virtual machine disk, it will be SUSE 11.

It might take a longer while, depending how fast is the storage and how big is the machine. Start VM – but it will not boot 🙂 because mbr tool change block for root partition from 63 to 64.

grub prompt

grub prompt

Recover GRUB boot loader on Linux VM – in my case SUSE 11
  • Boot from ISO with SUSE 11 OS
  • From boot menu choose Rescue System
SUSE rescue system

SUSE rescue system

  • Login to rescue console as a root – without password
  • Type commands as below:

GRUB fix

GRUB fix

  • Reboot VM
  • DONE

VM should boot correctly like on the figure below. Perform scan and aligned VM shouldn’t reported any more.

Boot menu from SUSE 11

Boot menu from SUSE 11


In case of problem with recovering VM after alignment, you can reconfigure VM to use virtual machine backup files

Artur Krzywdzinski

Artur is Consulting Architect at Nutanix. He has been using, designing and deploying VMware based solutions since 2005 and Microsoft since 2012. He specialize in designing and implementing private and hybrid cloud solution based on VMware and Microsoft software stacks, datacenter migrations and transformation, disaster avoidance. Artur holds VMware Certified Design Expert certification (VCDX #077).