Can’t find/create new VMFS datastore after removing old one using Add Storage Wizard

by

 

Yesterday I was doing some out of hours work for a client who had a VM on a VMFS 3 datastore that only had a 1MB blocksize, but needed a data disk larger than 256GB. Naturally, the datastore needed to be recreated with a larger blocksize, as it is in a vSphere 4 environment and running VMFS 3. I did a storage vMotion to move the data off the datastore, then removed the datastore using one of the ESX hosts. I checked the other ESX hosts and noticed it was still showing there too. Refreshing the storage on each solved this and the datastore disappeared as expected.

 

I then went to re-create the datastore, happy with the knowledge that our SAN would still be presenting the LUN to our ESX hosts. When I arrived at the Add New Disk/LUN wizard, I saw that the LUN was in fact, not showing. Here is the troubleshooting process I used to sort this issue out. It turned out to be two old ESX hosts that were decomissioned a short while back who were still “hanging on” to this datastore.

 

  • Checked each live ESX host for the Datastore and made sure it was removed
  • Rescanned each HBA on the ESX hosts for new storage etc…
  • Tried adding datastore again (still couldn’t find the storage)
  • Logged onto FC SAN and ensured the LUN was still being presented to all ESX hosts in the cluster
  • Used vCenter “Maps” feature to select “VM to Datastore” relationship to ensure no VMs were mapping to this datastore or trying to refer to it anymore (like CDs mounted etc).
  • Under Maps, I noticed the datastore in question was still visible at the very bottom, but nothing related to it – i.e. there were no branches to anything.
  • Went to Datastores view in vCenter, and saw the datastore still listed there but had “(inactive)” next to it’s name.
  • Highlighted the datastore and looked at it’s summary (see screenshot below for example) and saw 2 x ESX hosts still showing as connected to it. I then realised that these would be the old, decommissioned ESX hosts in the inventory still “holding on” to the datastore.
  • I removed these old hosts from the vCenter inventory, and the datastore was then gone. I was then able to re-create it and the presented LUN appeared in the add storage wizard as you would normally expect.
 
datastore showing as (inactive) even after removing it from all connected ESX hosts

 

2 x ESX/ESXi hosts were still connected to the old, removed storage, preventing it from being re-created (This example shows one with 5 hosts connected for reference)

 

So if you find yourself removing a datastore, and when arriving at the add new storage wizard and this LUN is not being presented back to you as an option to create a new datastore with, try the above troubleshooting steps to ensure nothing is still referencing the old, deleted datastore. Once sorted out, you should get the option back again.

 

2 thoughts on “Can’t find/create new VMFS datastore after removing old one using Add Storage Wizard”

  1. Hi Jake,

    Did you check the mappings area in your vSphere client to ensure all references were gone? Have you tried removing the VMs from your inventory then adding (re-registering) them again?

    Sean

  2. Nice article. I’m in a similar situation. I deleted a local datastore from one of our ESX 5 hosts. After removing the datastore vCenter showed it as inactive. I then realized that several VMs were still refering to this datastore. A few of the VMs had ISOs connected. Removing the ISOs took care of those VMs but I now have 2 VMS that are still referencing the old datastore. They have no disks, ISOs or snapshots on that datastore. How can I remove the refernce from these VMs to the deleted datastore?

Leave a Comment