You can set advanced options that affect the behavior of your vSphere HA cluster.

Table 1. vSphere HA Advanced Options

Option

Description

das.isolationaddress[...]

Sets the address to ping to determine if a host is isolated from the network. This address is pinged only when heartbeats are not received from any other host in the cluster. If not specified, the default gateway of the management network is used. This default gateway has to be a reliable address that is available, so that the host can determine if it is isolated from the network. You can specify multiple isolation addresses (up to 10) for the cluster: das.isolationaddressX, where X = 0-9. Typically you should specify one per management network. Specifying too many addresses makes isolation detection take too long.

das.usedefaultisolationaddress

By default, vSphere HA uses the default gateway of the console network as an isolation address. This option specifies whether or not this default is used (true|false).

das.isolationshutdowntimeout

The period of time the system waits for a virtual machine to shut down before powering it off. This only applies if the host's isolation response is Shut down VM. Default value is 300 seconds.

das.slotmeminmb

Defines the maximum bound on the memory slot size. If this option is used, the slot size is the smaller of this value or the maximum memory reservation plus memory overhead of any powered-on virtual machine in the cluster.

das.slotcpuinmhz

Defines the maximum bound on the CPU slot size. If this option is used, the slot size is the smaller of this value or the maximum CPU reservation of any powered-on virtual machine in the cluster.

das.vmmemoryminmb

Defines the default memory resource value assigned to a virtual machine if its memory reservation is not specified or zero. This is used for the Host Failures Cluster Tolerates admission control policy. If no value is specified, the default is 0 MB.

das.vmcpuminmhz

Defines the default CPU resource value assigned to a virtual machine if its CPU reservation is not specified or zero. This is used for the Host Failures Cluster Tolerates admission control policy. If no value is specified, the default is 32MHz.

das.iostatsinterval

Changes the default I/O stats interval for VM Monitoring sensitivity. The default is 120 (seconds). Can be set to any value greater than, or equal to 0. Setting to 0 disables the check.

Note:

Values of less than 50 are not recommended since smaller values can result in vSphere HA unexpectedly resetting a virtual machine.

das.ignoreinsufficienthbdatastore

Disables configuration issues created if the host does not have sufficient heartbeat datastores for vSphere HA. Default value is false.

das.heartbeatdsperhost

Changes the number of heartbeat datastores required. Valid values can range from 2-5 and the default is 2.

fdm.isolationpolicydelaysec

The number of seconds system waits before executing the isolation policy once it is determined that a host is isolated. The minimum value is 30. If set to a value less than 30, the delay will be 30 seconds.

das.respectvmvmantiaffinityrules

Determines if vSphere HA enforces VM-VM anti-affinity rules. Default value is "false", whereby the rules are not enforced. Can also be set to "true" and rules are enforced (even if vSphere DRS is not enabled). In this case, vSphere HA does not fail over a virtual machine if doing so violates a rule, but it issues an event reporting there are insufficient resources to perform the failover.

See vSphere Resource Management for more information on anti-affinity rules.

das.maxresets

The maximum number of reset attempts made by VMCP. If a reset operation on a virtual machine affected by an APD situation fails, VMCP retries the reset this many times before giving up

das.maxterminates

The maximum number of retries made by VMCP for virtual machine termination.

das.terminateretryintervalsec

If VMCP fails to terminate a virtual machine, this is the number of seconds the system waits before it retries a terminate attempt

das.config.fdm.reportfailoverfailevent

When set to 1, enables generation of a detailed per-VM event when an attempt by vSphere HA to restart a virtual machine is unsuccessful. Default value is 0. In versions earlier than vSphere 6.0, this event is generated by default.

vpxd.das.completemetadataupdateintervalsec

The period of time (seconds) after a VM-Host affinity rule is set during which vSphere HA can restart a VM in a DRS-disabled cluster, overriding the rule. Default value is 300 seconds.

das.config.fdm.memreservationmb

By default vSphere HA agents run with a configured memory limit of 250 MB. A host might not allow this reservation if it runs out of reservable capacity. You can use this advanced option to lower the memory limit to avoid this issue. Only integers greater than 100, which is the minimum value, can be specified. Conversely, to prevent problems during master agent elections in a large cluster (containing 6,000 to 8,000 VMs) you should raise this limit to 325 MB.

Note:

Once this limit is changed, for all hosts in the cluster you must run the Reconfigure HA task. Also, when a new host is added to the cluster or an existing host is rebooted, this task should be performed on those hosts in order to update this memory setting.

Note:

If you change the value of any of the following advanced options, you must disable and then re-enable vSphere HA before your changes take effect.

  • das.isolationaddress[...]

  • das.usedefaultisolationaddress

  • das.isolationshutdowntimeout