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Storage and HA

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Hi

If i didn't select any datastore would be HA able to check the storage heartbeat before reset the VM if vm app monitoring is enabled ?

Thank you

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VMware Employee
VMware Employee

A datastore heartbeat and a VM Tools heartbeat are two completely different things. They do share the same name though, which I concede can be confusing.

The datastore heartbeat in that image is simply a way for the HA node to determine if it's isolated from other hosts when the management network is down. If that is not checked, HA will not have that additional mechanism to determine the host state (partitioned, isolated, or failed)

The VM Tools heartbeat is something different and when OS monitoring is enabled it looks for I/O on the actual VMDK for that VM. It has nothing to do with the datastore heartbeat selected.

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VMware Employee
VMware Employee

If you don't select a datastore for HA datastore heartbeat this will just impact HA in isolation situations. It helps HA determine if a host is down or isolated.

VM app monitoring is using VMtools heartbeats, which is a totally different thing.

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Expert
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Thanks alot GS ,

I guess I need more help to clarify what Epping said  before restarting the VM Storage or Network I/O will be checked .Did I understand Duncan right ?

"One thing to keep in mind though is that when heartbeats are no longer received, by default sent out every second, VM Monitoring will check if there is any Network or Storage I/O to avoid false positives."

http://www.yellow-bricks.com/2010/06/04/vm-monitoring-aka-vm-ha-heartbeat/

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VMware Employee
VMware Employee

The VM Tools heartbeat is the first check to determine if the monitored VM is unresponsive. After a heartbeat is not received, HA will look for I/O coming from that VM. We look for both network and storage I/O. If I/O is detected, a restart will not occur. If no I/O is seen and the heartbeats are not detected, it a pretty high likelihood the OS within the VM has hung and HA will reset the VM.

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Thanks alot Matt,

In the graph that i shared shows no datastore been selected , Does that mean the storage I/O will not be counted by HA.

Or in both cases (datastore been selceted or not ) will participate in the HA heartbeat ?

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VMware Employee
VMware Employee

A datastore heartbeat and a VM Tools heartbeat are two completely different things. They do share the same name though, which I concede can be confusing.

The datastore heartbeat in that image is simply a way for the HA node to determine if it's isolated from other hosts when the management network is down. If that is not checked, HA will not have that additional mechanism to determine the host state (partitioned, isolated, or failed)

The VM Tools heartbeat is something different and when OS monitoring is enabled it looks for I/O on the actual VMDK for that VM. It has nothing to do with the datastore heartbeat selected.

View solution in original post

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