HA & FT Setup issues

[MJMSRI]

Hi All,

I have a vmware network setup and am looking to setup HA So i can shut one server down and all VM's will failover to other Host.

So i have vcentre server installed with:

2 x ESXI Hosts,

1 x iScsi datastore.

1 x datacentre

1 x cluster

Adapters with Vmotion and fault logging enabled.

2 X Virtual machines.

I have enabled HA on the datacentre and then also right clicked each VM and enabled FT.

However when i now attempt to start the VM's i recieve this error:

Any idea whats gone wrong?

Have i missed seting something up?

[a_p_]

So i can shut one server down and all VM's will failover to other Host...

Just to clarify. The purpose of HA and FT is to recover from host failures. In case of a planned host shutdown, it's DRS which live migrates the VM's to another host.

Regarding the error message, how did you configure HA Admission Control? With only two hosts, try to set 50% instead of # of host failures tolerated.

André

[a_p_]

... btw. consider to work with DNS/FQDN names rather than IP addresses for the hosts.

André

[MJMSRI]

Hi Andre,

I managed to resolve the issue i had earlier, so this is ok now, but i think ijust need some clarification on these solutions.

Firstly, Is FT required for HA or are they 2 individual failover solutions?

Is HA Required for FT?

I have now disabled FT on my two VM's.

As i understand it FT creates another shadow VM for every VM Where FT is enabled. The shadow VM is create on another ESXI host so if VM fails, the other VM starts, so FT is a solution for VM failures?

And HA is a solution for ESXI Servers Failover and any VMs that are running on them?

Thanks...

[a_p_]

HA and FT are two different approaches to provide continuity.

HA is able to monitor hosts and/or VMs and - depending on the configuration - restarts VM's in case the current host fails or the VM does not respond anymore.

FT goes one step further and - as you mentioned - created a shadow (secondary) VM on another host and - in case of a host failure - makes the secondary VM the active/primary one. FT does not protect from VM (OS) failures. If the OS fails (e.g. BSOD) this would also be mirrored to the secondary VM.

André

[MJMSRI]

Ok thanks for response.

So am I correct to say that HA also mirrors other hosts in the cluster so if one vm has BSOD on one esxi host then it's the same on all hosts in HA cluster?

So main benefit of HA is providing fail over for physical esxi hosts?

DRS only works with HA is that right?

Or does it work with FT aswell?

Sent from my iPhone 4S

[admin]

You have configured HA admission control using the "dedicated failover host" policy which prevents users from powering on any vms on the designated failover host (they are reserved for use by HA in event of a host failure). This is a problem in your case since you only have 2 hosts in the cluster and powering on an FT vm requires 2 hosts (one for the primary and one for the secondary). Consider using a different HA admission control policy.

Elisha

[chriswahl]

vSphere HA does not provide any mirroring. It simply watches the cluster for failed or isolated hosts. If this occurs, it restarts the VMs that were on the host elsewhere in the cluster.

DRS does not require HA. It helps distribute resources among the cluster.

[MJMSRI]

OK well i have enabled HA and added my 2 hosts so there is failover.

Is there a tester for HA to see if its configured correctly or whats the best way to test HA?

[depping]

best way to test HA is definitely to:

- isolate a host (remove all network cables) ---> fail-over of VMs should happen (depending on the chosen isolation response)

- pull powercords of a host --> fail-over should happen of VMs

- remove 1 network cable --> nothing should happen, assuming you have network redundancy configured

[MJMSRI]

With a default HA Configuration, including 2 x ESXI Hosts and 1 x virtual machine with the "Nostalgia" VM from the Market place (no vm tools installed)

Would HA work with this VM?

As i know HA monitors VM through Heatbeats via VM Tools, so if a VM does not have VM tools installed does this mean HA will fail for this VM?

Whereby i would need to install a Windows/Linux O/S, then install VM Tools on that VM for HA to work?

thanks

[a_p_]

HA can monitor ESXi hosts, VMs and even applications.

In the example you mentioned HA can only monitor the host, which means that if the host fails, the VM will be restarted on a surviving host.

André