Increasing LUN sizes on vSphere [ Weird Error]

imageNormally this is a super easy thing to get done but today I was working with a client and ran into such a weird error with the fix being buried in a forum post, I thought I would blog about it.

So my client is STILL running ESXi 5.5 and we were trying to upgrade a LUN and Datastore from 2TB to 4.3TB.   This LUN was a replicated LUN via RecoverPoint so we first went to each VNX and increased the LUN size on them.  No issues, worked great.  We then went to RecoverPoint and increased the replication set.  This had a caveat since we were running SRM. We needed to temporarily reset the management back from SRM to RecoverPoint and then edit and increase the size of the replication set.

But once that was done, it did it’s sweep and all was good on the RecoverPoint side.

In vCenter, we went to increase the Datastore but each time we went to properties, increase; We did no see the newly increased extent to expand the Datastore!


We even tried in the Web Client since we had read that certain functions above 2TB, the fat client would not cut it.

In the end, thanks to the blog post, we realized that we had to log into a SINGLE ESXi host as root and increase the LUN.  This worked successfully and then back in vCenter, we just did a typical rescan and all was good.


This is the kind of error that can eat time and drive you nuts.  it’s not a logical answer so I figured I would blog about it to help anyone else out there searching.  But like I linked in the beginning, if you are still running 5.5 in 2018, time to start prioritizing the upgrade to 6.x.

– Carlo