Put a host or datastore in a cluster under maintenance on VMware vSphere 6.7

2. Maintenance of a datastore

In business, you will need to maintain a datastore to:

• correctly upgrade the VMFS version of a datastore.
  Indeed, when you change the version of the VMFS file system of a datastore, VMware recommends formatting it after updating VMFS.
• move from one storage bay to another.
  You add the new datastores created on the new storage array and you place the old datastores for maintenance, one after the other, so that the data is automatically migrated to the new datastores.
• delete a datastore located on an old storage array.
  You add the new datastore, then place the old datastore on maintenance so that the data is automatically migrated to the new datastore.
• rename the files of virtual machines present on a datastore.
  Indeed, as explained in our tutorial "VMware vSphere 6.7 - Migrate VMs via vMotion (rename VM files)", when you rename a virtual machine, the name used for these files will remain the old name.
  To rename all the files at once, you can place the affected datastore under maintenance.
  Which will automatically rename the files of the VMs necessary so that the new name of the files of the corresponding VMs corresponds to the new name of the VMs.

2.1. Put a datastore in maintenance mode

In our case, our cluster has 2 datastores "iSCSI DS 1" and "ISCSI DS 2".
The 2 hosts in our cluster therefore have access to these 2 datastores.

On our "iSCSI DS 2" datastore, we can see that there are in particular the files of our "Win 10 x64 v2004" virtual machine.

To place a datastore in maintenance, select it and click: Actions -> Maintenance Mode -> Enter Maintenance Mode.

As indicated in the warning that appears, putting a datastore into maintenance requires that the virtual machines located there be migrated to other datastores.
To do this, check the box "Let me migrate storage for all virtual machines and entering maintenance mode after migration" and click "Continue".

In our case, we have a "Windows 10 x64 v2004" virtual machine on this datastore.
The migration assistant is therefore automatically displayed for this virtual machine.

Select "Change storage only" or "Change both compute resource and storage" to migrate files from this virtual machine to another datastore accessible by hosts in your cluster.

In our case, we wish to place our "iSCSI DS 2" datastore under maintenance.
So, we migrate our virtual machine to our "iSCSI DS 1" datastore.

Click Finish.

As expected, 2 tasks appear:

• Replace the virtual machine: migration of files from the VM located on the datastore to be placed under maintenance.
• Enter maintenance mode monitoring task SDRS: Waits for the virtual machines present on this datastore to be migrated to another datastore in the cluster.
  Hence the message that appears in the details column: "Wait until all VM files are migrated from the datastore".

Once the VMs have been migrated and maintenance mode has been enabled on the desired datastore, the 2 tasks will be completed.

As you can see, the files of our "Win 10 x64 v2004" virtual machine have disappeared from this datastore.

As expected, our virtual machine has been migrated to our "iSCSI DS 1" datastore.

2.2. Take a datastore out of maintenance mode

To exit a datastore from maintenance mode, select it and click: Actions -> Maintenance Mode -> Exit Maintenance Mode.

The "Exit SDRS Maintenance Mode" task appears and your database is no longer under maintenance.
Note that only the database icon tells you whether maintenance mode is activated on it or not.