6.0

e Set the I/O latency threshold.
Use the I/O Latency slider to indicate the maximum I/O latency allowed before Storage DRS is
triggered. Storage DRS makes recommendations and performs migrations when latency is higher
than the threshold.
NOTE The Storage DRS I/O Latency threshold for the datastore cluster should be lower than or
equal to the Storage I/O Control congestion threshold.
f Set the I/O imbalance threshold.
Use the I/O Imbalance Threshold slider to indicate the aggressiveness of I/O load balancing.
Storage DRS makes recommendations and performs migrations if the I/O load imbalance level
exceeds the threshold.
7 Click Next.
8 Specify the end settings for the task.
n
To restore the Storage DRS settings to the pre-task configuration, select the Restore settings check
box.
n
To specify settings other than the pre-task configuration, deselect the Restore settings check box.
9 Review the Ready to Complete page and click Finish.
The scheduled task runs at the specified time.
Storage DRS Anti-Affinity Rules
You can create Storage DRS anti-affinity rules to control which virtual disks should not be placed on the
same datastore within a datastore cluster. By default, a virtual machine's virtual disks are kept together on
the same datastore.
When you create an anti-affinity rule, it applies to the relevant virtual disks in the datastore cluster. Anti-
affinity rules are enforced during initial placement and Storage DRS-recommendation migrations, but are
not enforced when a migration is initiated by a user.
NOTE Anti-affinity rules do not apply to CD-ROM ISO image files that are stored on a datastore in a
datastore cluster, nor do they apply to swapfiles that are stored in user-defined locations.
Inter-VM Anti-Affinity
Rules
Specify which virtual machines should never be kept on the same datastore.
See “Create Inter-VM Anti-Affinity Rules,” on page 376.
Intra-VM Anti-Affinity
Rules
Specify which virtual disks associated with a particular virtual machine must
be kept on different datastores. See “Create Intra-VM Anti-Affinity Rules,”
on page 377.
If you move a virtual disk out of the datastore cluster, the affinity or anti-affinity rule no longer applies to
that disk.
When you move virtual disk files into a datastore cluster that has existing affinity and anti-affinity rules, the
following behavior applies:
n
Datastore Cluster B has an intra-VM affinity rule. When you move a virtual disk out of Datastore
Cluster A and into Datastore Cluster B, any rule that applied to the virtual disk for a given virtual
machine in Datastore Cluster A no longer applies. The virtual disk is now subject to the intra-VM
affinity rule in Datastore Cluster B.
Chapter 25 Resource Management for Single Hosts
VMware, Inc. 375