6.5.1

Table Of Contents
vCenter Server automatically selects a preferred set of datastores for heartbeating. This selection is
made with the goal of maximizing the number of hosts that have access to a given datastore and
minimizing the likelihood that the selected datastores are backed by the same storage array or NFS
server. In most cases, this selection should not be changed. To see which datastores vSphere HA has
selected for use, in the vSphere Web Client you can go to the cluster's Monitor tab and select vSphere
HA and Heartbeat. Only datastores mounted by at least two hosts are available here.
Note There is no heartbeat datastore available if the only shared storage accessible to all hosts in the
cluster is vSAN.
User-Preferred Datastore is Not Chosen
vCenter Server might not choose a datastore that you specify as a preference for vSphere HA storage
heartbeating.
Problem
You can specify the datastores preferred for storage heartbeating, and based on this preference, vCenter
Server determines the final set of datastores to use. However, vCenter Server might not choose the
datastores that you specify.
Cause
This problem can occur in the following cases:
n
The specified number of datastores is more than is required. vCenter Server chooses the optimal
number of required datastores out of the stated user preference and ignores the rest.
n
A specified datastore is not optimal for host accessibility and storage backing redundancy. More
specifically, the datastore might not be chosen if it is accessible to only a small set of hosts in the
cluster. A datastore also might not be chosen if it is on the same LUN or the same NFS server as
datastores that vCenter Server has already chosen.
n
A specified datastore is inaccessible because of storage failures, for example, storage array all paths
down (APD) or permanent device loss (PDL).
n
If the cluster contains a network partition, or if a host is unreachable or isolated, the host continues to
use the existing heartbeat datastores even if the user preferences change.
Solution
Verify that all the hosts in the cluster are reachable and have the vSphere HA agent running. Also, ensure
that the specified datastores are accessible to most, if not all, hosts in the cluster and that the datastores
are on different LUNs or NFS servers.
Unmounting or Removing Datastore Fails
When you try to unmount or remove a datastore, the operation fails.
vSphere Troubleshooting
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