How are you connecting your virtual machines to their disks?

[pete]

I'm undecided how to present the disks to virtual servers if we increase our (currently meagre) investment in virtualisation. In my test environment (Xen and ESXi), I've been using nfs and iscsi and all things being equal, I prefer nfs. I wondered how others were doing it?

 

How are you connecting your virtual machines to a) their system disks and b) any additional storage they provide to clients? Why did you choose that method? Would you still do it that way if you were doing it now?

[dhicks]

How are you connecting your virtual machines to a) their system disks and b) any additional storage they provide to clients?

 

All disks (system and data) used by VMs are logical volumes, held on a local RAID array and mirrored via DRBD to another machine. This way we can flexibly resize volumes, we get local disk performance (no latency in getting the data over a copper connection, or high cost in buying fibre channel) and if a machine conks out another one takes over.

 

Why did you choose that method?

 

Because it's best :-) It gives best disk performance to VMs and the money we save on not buying fibre channel networking kit lets us have duplicate machines to mirror each VM.

 

Would you still do it that way if you were doing it now?

 

Ideally, starting from scratch, we would have around 4 really nice big servers (dual 4-core processors, 16GB of RAM, etc), each with a expandable RAID array. Two machines and a decent switch in a half-height cabinet in two seperate locations in the school, linked via standard pre-terminated fibre. One machine in each cabinet would also act as an Internet gateway, so we would have two Internet connections for redundancy. Our current kit is put together mostly out of parts from eBay.

 

--

David Hicks

[cookie_monster]

Any new thoughts on this guys?

 

We are about to buy 2 Sun Fire X4150 servers and a 7110 Sun SAN we will be virtualizing about five servers to start 2003 and 2008. I'm not sure of the best way to go should we virtualize the OS on the local RAID array on the Sun Fire boxes or is it better to have the virtual HD's on the SAN device? We then plan on having all of the data on the SAN.

 

Also to help me size our storage how much space should I allocate per OS does the hypervisor keep a mirrored copy that I should factor in or is this good practice.

 

Thanks.

[DAckroyd]

failed to spot that it was multi-choice... use SAN over Fibre Channel (only ticked FC)