How to Remove a Datastore

Intro

Hey everyone,

I figured I’d write up a quick little help guide on removing a Datastore. Now this isn’t new and likely to be buried on the internet because of it. However in my searches I have found the following sources to be great reads. I highly recommend you check them out.

1)  Official Source VMware KB2004605.

2) A Blog guide by Sam McGeown, here.

3) A post by Mike on cswitchzero.

Now let’s go through the checklist from the official source one by one.

Check List

• If the LUN is being used as a VMFS datastore, all objects (for example, virtual machines, templates, and Snapshots) stored on the VMFS datastore must be unregistered or moved to another datastore.-This one is pretty easy navigate to the datastore files and check. You may find some remanence from the following though.
• All CD/DVD images located on the VMFS datastore must also be unmounted/unregistered from the virtual machines.-This shouldn’t even be the case if you did check one.
• The datastore is not used for vSphere HA heartbeat.-This setting will use a folder labeled “.vSphere-HA”
  For a Quick overview of Datastore Heart beating See here
  To “remove” aka change them See here
• The datastore is not part of a datastore cluster.-You can find useless help on this process from VMware here. I’m assuming it’s an easy task via the WebUI
• The datastore is not managed by Storage DRS.-If you removed it from the datastore cluster, how could this be an issue?
• The datastore is not configured as a diagnostic coredump Partition/File and Scratch Partition. For more information, see the following:
  • Configuring a diagnostic coredump partition on an ESXi 5.x host (2004299)
  • Configuring ESXi coredump to file instead of partition (2077516)
  • Creating a persistent scratch location for ESXi 7.x/6.x/5.x/4.x (1033696)-This is very important, glad the official guide covers it. Neither Mike or Sam seemed to have covered this part. I was able to notice this simply from again verifying the first item in the Checklist. You’ll notice this stuff if you are actually validating the files that reside on the datastore to ensure nothing is there.
• Storage I/O Control is disabled for the datastore.-See here on how to enable (disabling is the exact reverse)
• No third-party scripts or utilities running on the ESXi host can access the LUN that has issue.-Honestly I’m not sure how you could check this… even when doing some quick research, you can have scripts I guess that are not on the hosts, but run by alternative machines via PowerCLI. As described in this community post. I guess you’d have to know, either way the scripts would just fail, shouldn’t affect the vSphere cluster.
• If the LUN is being used as an RDM, remove the RDM from the virtual machine. Click Edit Settings, highlight the RDM hard disk, and click Remove. Select Delete from disk if it is not selected and click OK.Note: This destroys the mapping file but not the LUN content.

  – This is more involving the removing of the backend physical device. Which in my case is the final goal. Though if yours was just to remove a datastore while keeping the physical storage in place this can be ignored.

• As noted by Sam but not the official source or Mike is if you see a .dvsData folder. as stated by SAM “The .vdsData folder is created on any VMFS store that has a Virtual Machine on it that also participates in the VDS – so by migrating your VMs off the datastore you’ll be ensuring the configuration data is elsewhere.”
• Check that there are no processes locking the VMFS with this command:

esxcli storage core device world list -d

Datastore Removal Steps

Step 1) Follow the Checklist above.

Make sure no files reside on the Datastore.

Step 2) Unmount Datastore from all ESXi hosts.

As noted by SAM blog post even in vSphere 5.x using the C# phat client, this was possible to do via a wizard against all hosts that have the datastore mounted. Even on the newer HTML5 WebUI this is still possible (I think everyone wants to fully forget that VMware chose flash for a short time).

At this point the Datastore will show up as inaccessible to vSphere. As noted by both Mike and Sam. This will be the same anywhere from 5.x-7.x (As noted by Mike it might be slightly more important to follow procedures with earlier versions of ESXi 3 or 4). If the Check list was followed, there should be no issues unmounting the datastore.

If you need to do this via esxcli (Source):

# esxcli storage filesystem list

Unmount the datastore by running the command:

# esxcli storage filesystem unmount [-u UUID | -l label | -p path ]

For example, use one of these commands to unmount the LUN01 datastore:

# esxcli storage filesystem unmount -l LUN01

# esxcli storage filesystem unmount -u 4e414917-a8d75514-6bae-0019b9f1ecf4

# esxcli storage filesystem unmount -p /vmfs/volumes/4e414917-a8d75514-6bae-0019b9f1ecf4

Step 3) Detach the LUN from all hosts.

As noted by Sam, if you are on 5.x you might want to automate this via PowerCLI. Then noted by Mike, newer 7.x can now do this in bulk via the Management WebUI.

6/7 WebUI -> Hosts n Clusters -> Hosts -> Cluster -> Host -> Configure Tab -> Storage Device (left side tree) -> Highlight Device -> Detach

for esxcli

Obtaining the NAA ID of the LUN to be removed

esxcli storage vmfs extent list

To detach the device/LUN, run the command:

# esxcli storage core device set --state=off -d NAA_ID

6. To verify that the device is offline, run the command:

# esxcli storage core device list -d NAA_ID

The output, which shows that the Status of the disk is off.

Step 4) Rescan HBAs

At this point, if you rescan all HBAs on all hosts the inaccessible datastore should be gone from the WebUI.

At this point you can remove the LUN from being seen (disc from showing up under devices) this will either be iSCSI based configurations (remove static and dynamic IPs from the iSCSI initiator settings on each host.) Mostly likely for a shared VMFS datastore.

It could be a local disc over a local storage controller (such as a logical drive created in RAID) such as behind a Pxxx storage controller.

Removing the source device will always be dependent on how it was configured in the first place.

Summary

So today we covered removing a Datastore. The important thing to remember is removing a Datastore takes a lot more steps than removing one, cause so many different VM’s and services can be applied to a datastore once it has started being used.

In many cases, the SysLog and Scratch partition are big hang ups, and should be looked at closely. Which, however, as stated if you are actually checking for files on the datastore this stuff will be pretty evident.

In most cases, ensure you follow the check list and the process should be pretty smooth. Hope this helps someone.

*Note* I often provide screen shots to provide some context, in this case I decided to leave it more generic to span multiple versions of vSphere.