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MOSS 2007 on a Hyper-V cluster

  Asked By: Madhu    Date: Jan 10    Category: MOSS    Views: 878

Anyone using MOSS 2007 on a Hyper-v Failover Cluster (highly available)? I've
got a few questions that I have not been able to find answers scouring the
internet. Here's what I have:

- 2x Dell R900s (each server has: 64gb/ram, 2 4-gb HBAs, 1x 4-port nic)

- Windows Server 2008 Core setup with Hyper-v/Failover clustering.

- Enough LUNs to do pretty much whatever I want.

Here's where my issue comes into play: when I create a guest, it requests for a
location to store its Hyper-V configuration (not a VHD, because we're using pass
through disks). When the guest gets created, the resource consumes its pass
through disk, and the cluster disk that contains our Hyper-V configuration
storage location. From what I'm seeing, each guest requires ~2gb of space for
its configuration. Ideally you would create separate cluster disks to store this
....but it appears you could also do a NFS share as a cluster resource. The
moment I create my 2nd highly available guest, System Center Virtual Machine
Manager shows a "Unsupported Cluster Configuration" ...which I'm assuming is
because my guest is sharing a resource with another guest.

...anyone else had any pains like this?



4 Answers Found

Answer #1    Answered By: Felecia Goff     Answered On: Jan 10

The 2GB is going to vary with the size of the RAM assigned to the guest
- Hyper-V pre-allocates enough space for the Saved State file
(essentially a RAM dump) for each running VM. You *don't* want to use
NFS/SMB for this - while it's not specifically disallowed, it not
supported and generally considered a bad idea. Use an iSCSI or SAN LUN
for it. SCVMM requires no more than 1 HA VM per LUN, so if you are not
storing everything involved in the VM guests on a unique LUN (including
the configuration) you will get this error. To store more than 1, you
need to be using Clustered Shared Volumes which required the Hyper-V in
Windows Server 2008 R2 RC.

Answer #2    Answered By: David Scott     Answered On: Jan 10

When you say unique LUN (including the configuration), you basically need a pass
through disk + another disk (not being used by any other guests) for the saved
state file? How do you estimate how much you're going to need for that other
disk? I currently have 40gb luns for my guests, then I'll need another lun
(equal to the amount of ram I've assigned to the system)?

Answer #3    Answered By: Lakeshia Gould     Answered On: Jan 10

If you are committed to using a pass through disk, yes, you will need 2
LUNs per VM. If you use a fixed VHD instead of a passthrough disk (very
similar performance), you only need 1 LUN per VM. The configuration
files include:

1) A saved state file which is equal to the RAM associated with the

2) Any snapshot files. The actual size will vary a lot depending
on the number of snapshots and how much content they contain. Could be
anywhere between 0(no snapshots) and the number of snapshots x the size
of the original disk (if each snapshot contains a LOT of changes).

3) A few KB for misc xml config files, some of which get stored on
the system disk of the host

Answer #4    Answered By: Lizbeth Macdonald     Answered On: Jan 10

We figured this out yesterday... we're going to use passthrough + 1 lun for the
configuration. Works like a champ so far.

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