Ok. We recently experience this when adding new storage on ESXi host takes awhile when you have multiple “new” LUNs presented on the host.
The setup is common for environments with LUN replication and you would be attaching the LUNs manually on the DR site.
Apparently, this is normal as ESXi is making sure that the “new” LUNs is not owned by anyone. In the wizard, it takes 30 seconds per Datastore to test this.
[VMware KB article describing the behaviour here: https://kb.vmware.com/kb/1011387 ]
Unfortunately, if you’re operating on multiple datastore – this will increase significantly.
To get around this, you need to disable the following check: VMFS.UnresolvedVolumeLiveCheck . This skips ESXi level check and lets you around doing this.
NOTE though: MAKE sure the LUN’ you’ll be operating on is not used by any other systems or you’ll be in for a suprise when you accidentally mount it 🙂
PowerCLI Script One liner on how to change it:
Get-AdvancedSetting -Entity (Get-VMHost <VMHost Here>) -Name VMFS.UnresolvedVolumeLiveCheck | Set-AdvancedSetting -Value “False”