Resolved -- SureBackup, vCLS and VeeamBackup datastore

[Frosty]

Just posting this in case it helps someone else.

We run SureBackup jobs weekly, but they started failing within about 1 min of job starting.
Log for job showed errors:
SureBackup operation has failed
Failed to connect backup datastore to the ESXi host ...
Fault "ResourceInUseFault ..."

Found these useful articles which showed me where to look:
https://www.veeam.com/kb4504
https://knowledge.broadcom.com/external ... cyId=80472
https://knowledge.broadcom.com/external ... cyId=91890

What worked for me was the following steps:
* verified that the VeeamBackup_<serverName>etc SureBackup datastore had a vCLS VM in it
* verified that the VeeamBackup_<serverName>etc SureBackup datastore status was Inaccessible
* verified that couldn't migrate this vCLS VM to another datastore because of Inaccessible status
* put cluster into Retreat mode (see link above)
* waited for all vCLS VMs to disappear
* unmounted the VeeamBackup_<serverName>etc datastore
* re-established vCLS mode (reverse Retreat mode step)
* wait for vCLS VMs to be re-created and started
* rebooted our backup server (probably not necessary step)
* run SureBackup job and verified working again