6.7

Table Of Contents
Procedure
1 Perform an upgrade of the locking mechanism by running the following command:
esxcli storage vmfs lockmode set -a|--ats -l|--volume-label= VMFS label -u|--
volume-uuid= VMFS UUID.
2 For an online upgrade, perform additional steps.
a Close the datastore on all hosts that have access to the datastore, so that the hosts can
recognize the change.
You can use one of the following methods:
n
Unmount and mount the datastore.
n
Put the datastore into maintenance mode and exit maintenance mode.
b Verify that the Locking Mode status for the datastore changed to ATS-only by running:
esxcli storage vmfs lockmode list
c If the Locking Mode displays any other status, for example ATS UPGRADE PENDING, check
which host has not yet processed the upgrade by running:
esxcli storage vmfs host list
Change Locking Mechanism to ATS+SCSI
When you create a VMFS5 datastore on a device that supports the atomic test and set (ATS) locking, the
datastore uses the ATS-only locking mechanism. In certain circumstances, you might need to downgrade
the ATS-only locking to ATS+SCSI.
You might need to switch to the ATS+SCSI locking mechanism when, for example, your storage device is
downgraded. Or when firmware updates fail and the device no longer supports ATS.
The downgrade process is similar to the ATS-only upgrade. As with the upgrade, depending on your
storage configuration, you can perform the downgrade in online or offline mode.
Procedure
1 Change the locking mechanism to ATS+SCSI by running the following command:
esxcli storage vmfs lockmode set -s|--scsi -l|--volume-label= VMFS label -u|--
volume-uuid= VMFS UUID.
2 For an online mode, close the datastore on all hosts that have access to the datastore, so that the
hosts can recognize the change.
Snapshot Formats on VMFS
When you take a snapshot, the state of the virtual disk is preserved, which prevents the guest operating
system from writing to it. A delta or child disk is created. The delta represents the difference between the
current state of the VM disk and the state that existed when you took the previous snapshot. On the
VMFS datastore, the delta disk is a sparse disk.
vSphere Storage
VMware, Inc. 163