New to VMware, question about fail-over redundancy.

[RoblLaw80]

Hi all. Currently I'm looking into replacing all of my company's aging physical servers, and the possibility of using virtualization came up. Since VMware's sales rep. seems to be a bit slow on getting back to me, I thought I'd post what I'd like to accomplish and hopefully get some feedback.

Currently I have five servers running Windows Server, but a couple more will be needed in the near future. What I'd like to do is set up two physical machines running virtual servers, and have fail-over features in the event that one of them dies the other will take over the VMs that were running on the now dead server. I assume to do this would require something like an iSCSI storage device to house the virtual machine files and have VMWare's VMotion running, correct?

Any thoughts or opinions on which products I should be looking at for this?

[Dave_Mishchenko]

Hi Rob, you are correct in that you'll need some sort of shared storage and that could be iSCSI, NFS or FC SAN. VMware has a high availability option that would take care of this for you. It basically restarts a VM on another host if a failure is detected on the host that was running the VM. It's not quite like vmotion in that the VM does restart completely (as if someone pulled the power plug on it), while with vmotion the VM is transfered while it is still running.

Alternatively, you could consider products that replicate the VMs between storage. That would allow you to stick with local storage and give you a bit of a disaster recovery ability should the iSCSI device and primary host both go down.

[RoblLaw80]

Does using either of those require a VMware VirtualCenter Management Server?

[Dave_Mishchenko]

VMware's High Availability option does require VirtualCenter, but products like Vizioncore's vReplicator can work without it. Vizioncore does offer a SMB bondle of ESX starter, replicator and a few other products: http://www.vizioncore.com/vdrsmb.html. There are alternative to the Vizioncore product as well and you could do this all with scripting if you wanted to as well.

[RoblLaw80]

Thanks for all the info. One last question. Is the VirtualCenter software something that goes on a server all it's own, or is it just a managemnt console program to be run from a workstation?

[Dave_Mishchenko · Accepted solution]

VC consists of Windows services and a database (SQL Server / Oracle). You usually run this on a dedicated server but you can run it in a VM as well (http://www.vmware.com/pdf/vi3_vc_in_vm.pdf). The VC install has an option to install MSDE as well to use for the database, but it isn't supported for production use (works OK for a small farm).

You then use the VI client to manage VC (and the ESX hosts). You can run the client either on the server running VC or on your PC.

[RoblLaw80]

Well, I thought that was the last question...

One thing I'm not sure on is, what kind of storage device would give enough throughput for that kind of setup? Some of our servers can get some pretty heavy disk activity at times. The exchange server typically doesn't get hit too hard as it has 50 users on it. But when you start adding other servers ontop of it, I imagine the storage device could get pretty busy. I was looking at an adaptec iSCSI storage unit with with 4 250Gb SAS drives running RAID5 when I first started looking into this, but now I'm wondering if I shouldn't find something with more smaller and faster drives.

[Dave_Mishchenko]

If your physical servers are heavily using say 10 disks right now then you could likely end up with issues moving to the Adapter unit. Which unit is it by the way? VMware only supports the 7x0i models - see this document for a list of support iSCSI targets: http://www.vmware.com/pdf/vi3_san_guide.pdf

Do you have a preference of hardware vendor? Dell, HP and IBM offer entry level iSCSI devices that might provide the I/O you need and there are other options available if you have pick the solution you want.

[RoblLaw80]

I forget exactly which model it was. It's from when I was first looking at Microsoft's virtual server which we're definately not going to go with. Currently all of our servers are using a total of 20 drives. Two 4-disk RAID-5 sets, one of which hardly ever gets used anymore, and six 2-disk RAID-1 sets for the OS's and the couple of databases we use. I'm thinking of recomending something that has 8-10 SAS drives, and around 700Gb-1Tb of storage.

[AZ-Tech]

Rob not sure what your budget is on this but we are looking at the same options for about 20 servers.

Dell has some entry level ISCI San solutions with SAS drives or FC.

We are going the FC route because of the number of servers and the IO associated with our database servers.

Since Dell partnered with EMC they are putting out some nice SAN options.