HA admisstion control

[victorarok]

Hi,

Need your help in understanding this.

I have cluster running 10 host with esxi5.0.With HA and DRS enabled in shared storage.

What happens if all the 9 host fails .Will all the vms poweron on the working host.I have admisstion control policy disabled.

Please help me .

Thanks,

[admin]

It depends on the number of VMs and available resources on the working host. If the working host has sufficient resources to poweron N Vms, then YES.

(Assuming overall N VMs in 10 hosts)

Other key issues that need to considered here:

  - If N is large, failing over N vms on a single host might slow down the host significantly. For e.g.

     - Resource contention (cpu, mem, storage, interconnect, etc) contention during restart/powerOn (boot storm)

- Resource usage (e.g. cpu, mem, ...) after VM powerOn

- N does not exceed ESX maximum (Note, there is a limit of number of VMs per ESX host)

[depping]

victorarok wrote:

Hi,

Need your help in understanding this.

I have cluster running 10 host with esxi5.0.With HA and DRS enabled in shared storage.

What happens if all the 9 host fails .Will all the vms poweron on the working host.I have admisstion control policy disabled.

Please help me .

Thanks,

That depends. Only requirement there is in order to start a virtual machine is that ALL reserved resources are available. Now typically you will not have any, except for the "overhead" memory of a virtual machine which you should be able to guarantee as well.

It should be noted, that if you ever reach this point... your VMs will be dog slow though