Virtual Server Infrastructure

[mitchell1981]

Just wanted to ask about virtual server system design when using a SAN.

 

I have five physical servers connected to a SAN box. The physical servers boot from their own hard disks but the virtual servers will run from the SAN.

 

I want to run about three virtual machines on each physical server. What is the best way to configure this?

 

If I take one server as an example. I want to set up a file server so it will need two volumes. A system volume and a studentdata volume.

 

So the options appear to be:

 

1) Create one volume on the SAN and attach it to the physical server. Then create two VHDs on the volume, one for the system disk and one for the data disk, and allocate them to the virtual machine.

 

2) Create two volumes on the SAN and put a VHD file on each volume, one for the system disk and one for the data disk and attach them to the physical server, then allocate them to the virtual machine.

 

3) Create two volumes on the SAN, use a VHD for the system disk, attached to the phsical server. The data volume would be attached directly to the virtual machine and not use a VHD file at all.

 

Anyone know which is the approved method or am I thinking completely along the wrong lines?

 

I'm also concerned that with the release of the new version of Hyper-V and the ability to live-migrate servers, it is important that all physical servers can have access to all volumes on the SAN, but I don't see how this is possible with any of these configurations!

 

Finally if anyone knows of a good guide to network design using virtual servers then that would be great.

[cookie_monster]

You could set this up in many different ways depending on your SAN how do you connect to your SAN e.g iSCSI, fibre? This is how we have our setup using Xenserver.

 

We have two physical servers and a SAN all the physical servers run on their own disks is Xenserver the Windows system C: drives are on the SAN as VHD's currently we have three VM's per LUN. I would keep your OS system drives and data drives on separate LUNs. For our file servers we then created another LUN and then used Xenserver to create another VHD that is then presented to the Windows hosts as the D: data drive, as far as the Windows OS is concerned this is attached storage. That's pretty much what you described above in point 2 really.

 

One important point is that as far as I'm aware live migration requires the source and destination processor architecture to be very similar if not identical.

Edited September 5, 2009 by cookie_monster

[PiqueABoo]

I'm also concerned that with the release of the new version of Hyper-V and the ability to live-migrate servers, it is important that all physical servers can have access to all volumes on the SAN, but I don't see how this is possible with any of these configurations!

 

Look into HV R2's Clustered Shared Volumes.

[mitchell1981]

Thanks. I've had a look and this looks to be exactly what I need. Found a good guide here:

 

Clustering and High Availability : Deploying Cluster Shared Volumes (CSV) in Windows Server 2008 R2 Failover Clustering

 

Of course setting it up is going to be tricky on a live system. Perhaps I'll wait until the next holiday!

 

If anyone has tried this already please share your experiences.

 

Thanks.