VSAN-Troubleshooting-Reference-Manual

Diagnostics and Troubleshooting Reference Manual – Virtual SAN
Common storage problems and resolutions
The following is a list of some of the most common storage issues that customers
reported with Virtual SAN.
Virtual SAN claiming disks but capacity not correct
There have been occasions where customers report that the capacity of the VSAN
datastore is not shown correctly. We have seen this situation when a customer
replaced or changed components on a host that also changed the way the local SCSI
disks were presented to the ESXi host. This caused the local VMFS-L volumes on
those disks to show up as snapshots and an ESXi host does not mount snapshot
volumes by design. The disks are displayed as In CMMDS: false in the output of the
esxcli vsan storage list as shown below:
naa.600605b008b04b90ff0000a60a119dd3:
Device: naa.600605b008b04b90ff0000a60a119dd3
Display Name: naa.600605b008b04b90ff0000a60a119dd3
Is SSD: false
VSAN UUID: 520954bd-c07c-423c-8e42-ff33ca5c0a81
VSAN Disk Group UUID: 52564730-8bc6-e442-2ab9-6de5b0043d87
VSAN Disk Group Name: naa.600605b008b04b90ff0000a80a26f73f
Used by this host: true
In CMMDS: false
Checksum: 15088448381607538692
Checksum OK: true
Because the volumes were not mounted, they could not be used to add capacity to
the VSAN datastore. In this case, the volumes were identified and
resignatured/remounted for them to be added back into CMMDS and thus added to
the capacity of the VSAN datastores. Customers with this issue should reference KB
article 1011387 or speak to Global Support Services for advice.
Virtual SAN not claiming disks - existing partition information
A common question is how to repurpose disks that were once used by Virtual SAN
but you now wish to use these disks for other purposes? In Virtual SAN 5.5, when
you place the host into maintenance mode and remove the disk group from the host,
this will automatically remove the partitions from the disks and these disks can now
be used for some other purpose.
In Virtual SAN, individual disks can be removed from a disk group, also removing
the disk information including partition information.
However, if ESXi is reinstalled on the host that was running Virtual SAN but the
appropriate Virtual SAN clean up steps were not first followed, then there may still
be Virtual SAN partition information on the disks. This next section will detail how
to go about cleaning up these disks.
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