VCenter VM vs. Physical

[Survbase]

We are running 12 virtual machines on a single server and have a second server as failover. Each server has 4 nic’s plus IPMI. VMDK’s are stored on a NAS using iSCSI. We are in the process of configuring failover and have questions about how to proceed. The objective is to have unattended failover....

For the VMware Vcenter Server software that manages the cluster, VMotion, failovers, etc. is it beneficial to run on a dedicated physical machine vs. in a VM (the object is to have failover work without user intervention)? We are licensed for VSphere Advanced (Includes VMotion).

If it is not necessary to run Vcenter Server software on a dedicated physical machine, how is it configured to manage the failover?

If it is beneficial to run Vcenter Server software on a dedicated physical machine, could the VMware Vcenter Server be a remote server where WAN bandwidth is limited to 512K (I realize that there are probably quantity issues but I'm not sure what gets transferred in a failover - is this a small quantity of data - perhaps just machine information - or are is this a large quantity of data containing OSes, drivers, applications, etc.)?

If it is possible to have the VMware Vcenter Server be a remote server, but 512k is most likely insufficient, how would we determine what adequate speed would be?

Thanks,

-Micah

[weinstein5]

Welcoem to the Forums - when you say failover are you referring to VMware HA? If you are referring to VMware HA there is no problem running vCenter on a virtual machine because vCenter is used to configure and manage HA it is not necessary for vCenter to be running for an HA event to occur - if you are talking about vmotion to help you reco ver from an ESX server failure it will not work - vmotion requires running esx servers on either side -

No having vCenter remote is possible and you are correct you might lose connectivity to your ESX hosts but should not affect the running virtual machines -

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[AndreTheGiant]

See also:

Andre

[Survbase]

Thanks for that Andre. It was helpful to see the pros/cons layed out like that, however I still have questions. First off, we are using ESX4u1 and the latest VCenter with VMotion license. I understand that HA is a function between ESX hosts and VCenter is not needed for that. We are a small shop with not very many users, so load balancing is not really the goal. The main goal is availability of services/data within the organization. This means that I need to be able to perforn maintenance on the systems (OS and services) without bring all users offline (hence Live Migration). The other aspect is redundancy in case of failure; failover/failback or VMotion. I understand VCenter controls this. Also VCenter is required to manage the hosts as a cluster?

We have 2 custom quad core Xeon machines that makeup the cluster, connected to a 16TB linux NAS. The host will run 3 MS Server 2k8 guests, 4 winXP guests, a WIN7/Vista guest, and 2-3 CentOS guests. Will have MS Servers for Exchange, Sharepoint, DC,DNS,DHCP. I understand that enabling FT will automagically migrate these VMs (with VMotion) to the other host. If there is a major failure on the main host; ie complete power failure or NIC failure, will this still happen? Will VCenter still be able to move with the rest of the VMs and then take over management, or will it break?

I need a solid, reliable, easy to manage solution that will provide the best availablity given our current hardware. Any further advise will be appreciated.

[weinstein5]

FT really does not use vMotion - it actuallys ets up a shadow V running on the second ESX hosts so that if there is a problem with the primary VM the shadow takes over instantatneously - with what you describe I think you will best be served by HA which allows you to recover is a host fails or recover form a single VM failure -

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[AndreTheGiant]

VMware FT could be a solution if you need a high level of availability.

But it has several requirements and limits (for example each VMs must be 1 vCPU).

See also:

VMware HA could be fine in most cases (if you can wait about 5 min for the time that the VM is rebooted on the other node).

Andre