What is a VM Cluster

[hasole]

In the VI3 I&C course

Model 4: pg 58 it has a table of fc/iscsi/nas storage

It says no for VM cluster for iscsi and nas. Could someone please tell me what VM cluster is.

I thought it was Clusters for DRS/HA at first, but DRS/HA/VMotion all work on iscsi and nfs.

Cheers

[lholling]

Hi There

There have been a lot of changes since 3.0 for ESX. You have to remember that even if it works now the VI3 course is only based on 3.0. A lot of the iSCSI support for the hardware iSCSI HBA were deemed Experimental in 3.0

Here are the VMware definitions.

\# Clusters

A cluster is a collection of hosts that can be managed as a single entity. The resources from all the hosts in a cluster are aggregated into a single pool. A cluster looks like a stand-alone host, but it typically has more resources available.

\# VMware DRS

VMware DRS allows resources from all hosts in a cluster to be treated as a single, aggregated pool. When changes occur in the environment, DRS can tune the resource scheduling on individual hosts as well as use VMotion to rebalance workload across hosts in the cluster. When a virtual machine is powered on, DRS calculates the optimal host on which to start it, given current resource levels and the resource configuration of the new virtual machine.

VMware HA

VMware HA (HA) increases the availability of virtual machines by detecting host failures and automatically restarting virtual machines on other available hosts. HA operates on a set of ESX Server 3.0 hosts that have been grouped into a cluster with HA enabled.

Leonard...

[acr]

There are huge changes and developments in this space..

iSCSI is now fully supported, nfs is making great improvements..

I was at a workshop with NetApp and some of the performance from NFS was staggerring...

The speeds and recommendations are changing all the time..

[wcrahen]

They are referring to clustering of VMs in this instance. For example, 2 Windows 2003 server VMs runing MS Cluster Services. If you want to cluster 2 MS server VMs you need to have your ESX servers connected via a Fibre Channel SAN, and have those VM's system drives on local SCSI VMFS storage.

[hasole]

I see, so you think it is related to MSCS clustering.

Are you sure you can't do it using boot from SAN? Most of the local partitions are ext3.

[lholling]

I have to ask

What sort of clustering are you wanting to know about.

ESX Host Server clustering?

Clustering between virtual machines?

or

Booting an ESX Host from a SAN

Booting a VM from the SAN.

Leonard...

[wcrahen]

Correct MSCS. Technically you can do it, however local VMFS is what is offically supported.

[hasole]

Thanks, I've worked out that is it talking about MSCS clustering.