VMware 5.5 62TB vs. Old 1.8TB Restrictions

Here are some personal thoughts gathered in my travels and those that still insist there are limitations.  Perhaps it’s time for an upgrade?

VMware 5.5 supports 62TB disks.  Some ask why it isn’t 64TB – That is because a standard reserve of 2TB of disks space for snapshots etc. (5.1 heap issue with 30TB was a problem and some reference the old 1.8TB restriction)

To take an existing 2TB disc beyond the 2TB (1.8TB restriction) range you will have to power off the VM.  However, you can make the virtual disks bigger without a special conversion process involving a lengthy file copy process.

Disks with an MBR need to be converted to GPT in order to go beyond the 2TB limitation.  Currently, Windows 2008/2012 have no native tools to do this, however you can find 3rd party tools to assist.  – I prefer Partition Magic but there are other partition tools as well you might prefer.  Still, I highly recommend a backup before you start to play in production.  Should go without saying but hey … I’m just sayin’

Once the VMDK and the DISK in Windows is 62TB you may still face issue of “allocation unit” or small “cluster” size within the NTFS PARTITION.  NTFS defaults to 4K “allocation unit” size by default on smaller partitions, but to access a 62TB partition you need a “allocation unit” size of 16K or higher.  Some things to keep in mind as you navigate the waters to the monster in your datacenter.  Obviously this will depend on the limits, features of the file system, and Guest Operating System you need/want to set.  I’m becoming a bigger fan of NFS in these situations anyhow.