Friday, March 28, 2008

VM varoooomm...!

Was happy to see that Autotrader is switching over from iSCSI to NFS for its VMware storage layer. Good to see that Main Street is catching on.

Remember Kirby’s Law?

Simply stated – the proper location for virtualization is in the layer immediately above the resources to be virtualized.

You want to virtualize a bunch of servers, do it in the network connecting the servers.

You want to virtualize a bunch of processor cycles, do it in the software running on the processors.

You want to virtualize a bunch of storage arrays, do it in the network connecting the storage arrays.

You want to virtualize a bunch of disks, do in the controller connecting the disks to the network.

I am getting a kick out of xen-vm-ness being so screaming hot – saves $5k per instance per year, green green green – gotta do, do, do it, hot, hot, hot…

ya ok…go nuts…have fun

This ain’t rocket science – we’ve been virtualizing stuff since the sixties. You would think the vm-zen-whippersnappers invented it – hell, I was writing about why virtualization made so much sense before most of those little sh*ts got their first Gulfstreams.

Now – fair warning. There are a lot of nefarious speaker-posters who for various self-serving reasons are going to tell you that virtualization of one particular resource should be done several layers above it, in it, or below it – server virtualization software should be used to virtualize disks or some such hoowee.

Nonsense. You still doing disk mirroring on your host servers, are ya?

Kirby’s law always applies. Virtualize your storage in the layer right above it – not in it, not two levels above it.

If you are smart enough to understand that files are the smallest manageable logical storage entity to have business context, then you may already know the right place to virtualize storage today is in the network connecting the file servers to the application servers. If not, you soon will – as soon as you realize how limiting 16TB really becomes in a virtual server environment, for instance.

If you are virtualizing processor power with some sort of vm-zen-ness – good for you. However, before you go down the path of connecting virtualized servers to virtualized raw disk, consider that doing so means that you are ultimately going to be reliant on server virtualization to virtualize the raw disk two or three layers below.

This abrogates Kirby’s Law, is probably dumb, and will ultimately lead you down an ugly dark dead end path inhabited by proprietary ghosts and prohibitively expensive goblins.

If I am right, in a few years, the world will realize that using iSCSI or FC SAN with vm-zen-ness is stoopid.

Are you still hard-coding access control into your COBOL applications? No Duh…

Was I right about Flash? Yup…

If you are virtualizing your server environment – use NFS as your storage protocol. It’s better, period, end of story. Don't beleive me, ask Nick Triantos at NetApp. If you are ok with limited storage capacity, let a NAS storage controller virtualize your disk and present NFS to your virtual servers. If you want to protect yourself from lock-in and the pain of provisioning beyond a single NAS controller, do your virtualization in the network connecting your storage arrays to your virtualized servers.

People this is simple stuff – do not let the vendor obfustication blind you to the light.

Obey the law.

If you think I am wrong, see previous posts. I am not wrong.

My only question is how do I put my money where my mouth is this time?

1 comment:

curt said...

Great post, Kirby. u da man with Kirby's law.