An interesting conundrum …

I’ve just spent a few hours sitting through vForum2010 in downtown Sydney (right next to the beautiful harbour). Now these guys know their stuff, and are developing their products and product lines at an amazing rate of pace. From what I can see they must have an amazing number of developers bringing this stuff to market.

OK, thats enough niceties about VMWare (they didn’t give me any free stuff so my gratitude only stretches so far). I was interested in two main areas - storage (surprise suprise) and virtual desktops.

On the virtual desktop side they have made some amazing breakthroughs with the size of the data pools required to host a large number of desktops on a server. On the storage side, while I have no doubt they know exactly what they are doing, vmWare are totally focussed on SANs (especially fibre ones). This is in no doubt required to support some of their crazier technologies such as vMotion, and at the enterprise level is probably the dominant storage subsystem.

However … I know from the day-to-day grind of life that there are plenty of people using DAS (Direct Attached Storage) with VMWare. While you can’t do vMotion it is a great way of consolidating machines into lesser, cheaper, quieter, less power-hungry racks or individual boxes.

So why am I talking about all this? It’s been my experience that this is an area where the commonly-configured standard stand-alone server suffers when it comes to storage. Capacity is pretty easy to achieve if using SATA drives, but performance becomes complicated and generally under-done.

So how to fix this? You could go out and buy a fibre san (or even an iSCSI one for that matter) if you have enough money. You then probably need to go and get some skills, or employ a bod who knows about fibre channel zoning, masking and pathing. You would also find (and I’m talking to the SMB VAR here) that you price yourself out of your client’s price range.

So what to do. You want to use VMWare for the consolidation benefits, and you want to use the hardware that you are familiar with, that fits your customer price brackets and you know you can support. What you don’t want, however, is to sell your customer a pup that doesn’t perform.

So what are your options. You could use all SAS drives. You’ll need plenty of them with possibly an external JBOD to fit them all in. They cost quite a bit of money so you’re getting to the top end of your customer budget before you’ve even considered adding your services and support costs (which is where you make your real money).

Hmmm … those SATA drives are looking pretty good … big, cheap … don’t need a massive physical server to fit them all in … hmmm - I like them. However they scare the bejeezes out of me when it comes to performance. I’ll certainly be putting enough processor and RAM into the system to ensure that they can handle the workloads I’m going to put on the machine, but what do I do with the storage.

Pretty simply … cache it. By adding solid state caching to SATA drives you get excellent performance at a fraction of the cost of using all SAS drives. You can probably even afford to build in hot and cold spares while you are at it to make yourself and your customer feel good.

It’s worth considering …

Ciao
Neil