Newbie question on HA

[lawless007]

We are setting up 3 ESXi hosts and the plan is to run the vCenter server Suse linux appliance as we will only be running about 8 VM's max with the 3 hosts.

I understand that Fault Tolerance keeps VM's running in lock step so if  hardware server fails, next one picks up with no delay to end user.

My question is: With HA, which is what we will have in our Essentials Plus Kit, how often is the running VM replicated to the other two ESXi hosts. In other words, how much time do I lose if I have a hardware failure of the primary system running the VM's if I have to fire them up on one of the other hosts?

Question worded a different way: If it's not locked step, what is it exactly? How much will I lose?

I haven't started installation and setup at this time so excuse me if this question seems idiotic.

Thanks in advance for your answers.....

[a_p_]

HA does not do any replication at all. What HA does is to restart a VM on a surviving host in case the current host fails. To be able to do this the VM has to be on shared storage, available to all hosts.

André

[lawless007]

Thank you for the reply. One further question.

So if I use vCenter to format my NAS in the file system needed by vSphere 5 and import my VM's to there (currently in VMWorkstation 7 format), everything should be good to go with no further software needed other than what we purchased? We purchased the vSphere Essentials Plus Kit...

[a_p_]

As long as the NAS system is supported by vSphere 5.0 that's ok. To transfer the VMs from Workstation to ESXi you will need e.g. VMware Converter since ESXi cannot use the sparse virtual disk format used by VMware Workstation.

André

[lawless007]

Yea, already went through a testing phase of converting with the free Hypervisor. Got that part down. Again, thanks for your answer.

[Josh26]

Hi,

Some clairfication is in order.

Your question does refer to Fault Tolerance. This is a feature that uses the lockstep facility you referred to, in order to provide instantaneous failover.

However, your question subject refers to HA, which is a different feature. This provides a scenario where a hardware failure will cause your VM to reboot, and bring itself online on another host.

Your "essentials plus" kit licenses you for HA, but not fault tolerance.

Neither of these features provide any storage replica, however the Fault Tolerance does mirror the RAM.