HA will respond when the state of a host has changed, or when the state of one or more virtual machines has changed. There are multiple scenarios in which HA will attempt to restart a virtual machine of which we have listed the most common below:

• Failed host
• ISOLATED host
• Failed guest Operating System

Prior to vSphere 5, the actual number of restart attempts was 6, as it excluded the initial attempt. With vSphere 5.0 the default is 5. There are specific times associated with each of these attempts. The following bullet list will CLARIFY this concept. The ‘m’ STANDS for “minutes” in this list.

• T0 – Initial Restart
• T2m – Restart retry 1
• T6m – Restart retry 2
• T14m – Restart retry 3
• T30m – Restart retry 4

In case of a host failure, HA will TRY to restart the virtual machine on other hosts in the affected cluster; while performing the restart if this is unsuccessful on that host, the restart count will be increased by 1.

Let’s say first restart attempt is made at T0 minutes when the host failure has occurred (In actual restart is not performed as soon as host has failed because HA takes some time before declaring host failure; read above the 2 scenarios which I have mentioned).

If the first restart attempt is failed, then the restart counter is increased by one and the next restart is attempted after 2 minutes (T2). In the same fashion HA keep trying restarting the VM until issued power on attempt is reported as “completed”.

A successful restart might never occur if the restart count is reached and all five restart attempts were unsuccessful.

HA will respond when the state of a host has changed, or when the state of one or more virtual machines has changed. There are multiple scenarios in which HA will attempt to restart a virtual machine of which we have listed the most common below:

Prior to vSphere 5, the actual number of restart attempts was 6, as it excluded the initial attempt. With vSphere 5.0 the default is 5. There are specific times associated with each of these attempts. The following bullet list will clarify this concept. The ‘m’ stands for “minutes” in this list.

In case of a host failure, HA will try to restart the virtual machine on other hosts in the affected cluster; while performing the restart if this is unsuccessful on that host, the restart count will be increased by 1.

Let’s say first restart attempt is made at T0 minutes when the host failure has occurred (In actual restart is not performed as soon as host has failed because HA takes some time before declaring host failure; read above the 2 scenarios which I have mentioned).

If the first restart attempt is failed, then the restart counter is increased by one and the next restart is attempted after 2 minutes (T2). In the same fashion HA keep trying restarting the VM until issued power on attempt is reported as “completed”.

A successful restart might never occur if the restart count is reached and all five restart attempts were unsuccessful.