We're running quite a few MSCS clusters on Server 2012 R2 VMs. These have multiple shared storage drives that are RDMs.

 

We had a request to expand or increase the size of some of them.

 

When reading about this, ran across an old article that suggested the .vmdk "pointer" files on the datastores have to be re-created to present the additional storage. So, I set up a test to determine if this was something that remained accurate, or if VMware 6.0 can present the added storage all the way through the pointer file .vmdk to the OS level.

 

Our test scenario was essentially like this;

  1. Set up test RDM (123 Gb)
  2. Verify set up in Cluster and everything is normal.
  3. Request SAN increase size of RDM
  4. Determine if new size is presented to OS layer.

 

What actually happened;

  1. Recorded the UUID of the 123 Gb LUN
  2. Added 123 Gb LUN to each node of the cluster (adding the RDM to each node in VMware Web Client)
  3. Expanded the LUN on the SAN from 123 Gb to 223 Gb
  4. Re-scanned and refreshed storage adapters in Web Client (new size showed up)
  5. Logged into one of the Server 2012 R2 nodes and re-scanned disks.
  6. Observed the size; there was now an unallocated 100 Gb showing up on the target drive

 

Conclusion;

 

Even though old information suggested that the .vmdk "pointer" files had to be recreated to access the added space, this must have been updated in some version since the date of the article above. On 6.0, the newly added space was presented to teh OS without any additional steps after simply re-scanning and refreshing storage adapters.