How do you design your VHDs on Hyper V

[MrWu]

Hi all,

Just interested on your opinions on how you set you drives up on your Hyper V?

I have a Cluster with a MSA P2000 SAN with 6TB of storage, privisioning machines it got me thinking, I do have room but do you guys use fixed VHDs without fail(as per MS recommendations) and do you split them into C and D drives just like physical machine?

For example, I would build a VM with 100gb VHD for the OS (win 2008r2) and 200gb VHD for SQL DB, or a printer server with a 100gb OS drive and 100gb data drive for spool

On occasions like Impero and WSUS I woul risk using a single VHD that is dynamically expanding.

The problem with fixed VHDs is size, DPM backs it up as a whole partition and chews up disk space, and recovery for a 300gb+ VM will be slow.

So do you guys use fixed VHDs and how do you plan your backups and DR fo these big files?

Cheers all.

[glennda]

When building VM's I always use different VMDKs (Vmware equivalent of VHDs). I've also done both ways with Luns on the SAN as well (each vmdk on a lun and just large luns with mutliple vmdks on it). I can't say I have noticed a difference between it.

Personally I also create the disks with Fixed sizes rather than thin provision as you can cause problems for yourself.

[SYNACK]

Fixed disks are massively quicker, go with fixed if you can. They are also a bit more tollerant if stuff breaks for recovery purposes.

[RabbieBurns]

How long would it take to convert a 1.5TB dynamically expanding to a fixed disk, and can it be done online or should the server be offline?

[SYNACK]

How long would it take to convert a 1.5TB dynamically expanding to a fixed disk, and can it be done online or should the server be offline?

A long time and it's offline I think Quick conversion - Dynamic VHD to Fixed the convert process creates a whole new drive and copies the data across.

[MrWu]

Excellent.

Feel comfortable I have made the right choice (I try to treat VMs as building physical machines on best practice)

Will try out Veeam as well since it has dedupe and run this on a backup server off site too, so could switch over in case main computer room / SAN goes down.