ORIGINALLY POSTED 20th March 2009

11,899 views on developerworks

Funny, I had been thinking about blogging about a customer visit I had this week, primarily a new SVC user wanting to discuss and go into some deeper technical insight into the product. I enjoy these days as its a chance to talk techy with someone who is actually using and hopefully benefiting from the fruits of our labour here in development land.

The reason I say it’s funny is that this customer just got it. They saw the benefit and primarily the “commoditisation” aspects of SVC – and virtualization for that matter. Still, why funny, well Hu’s recent post makes the same point (I kind of agree with him for once!), and Martin posted a retort with his views that we (SVC and USP) shouldn’t be banging on about Virtualization, more about controllers.

I’m not quite sure I follow Martin’s thinking. To me, you could see USP as a controller – well it is, that happens to also virtualize storage – kind of as a second goal – but SVC is an appliance. Either way they both do provide commoditisation at a fundamental level. SVC more so, because the initial outlay for the hardware is much less (the footprint too) than a full frame USP – ok so the USP-VM is the USP-V without any disks but its simply the USP-V without any disks – still a fairly big box and quite expensive.

Is Martin suggesting that you buy the “controller head” and then can buy a common expansion unit for the drives, common across all vendors? So you pick and choose the head of your liking then buy commodity disk only units… interesting idea… but isn’t that exactly what SVC is?

Back to the customer I spent the day with, they got this completely. A mid-range RAID box is all you need. Even an entry RAID box (like IBM’s DS3400) is perfect for an intelligent head or appliance like SVC. Here you have RAID in a control unit that pretty darn cheap when it comes to storage, but can max out the 48 15K drives it supports. Perfect. No need for expensive controllers, just use the RAID and the secondary caching in the DS box and let the head – or virtualizer do the advanced stuff. Only pay for the advanced stuff if you want it. Thats commodity to me, and lets face it today RAID is a commodity. Almost every PC motherboard has it built in and pretty much expected. OK, so the RAID algorithms on a far eastern PC motherboard aren’t quite the same as RAID in a storage controller, but you get the point.

I spent most of the time discussing the internals of SVC, how it processes I/O, why the internal architecture is designed to be flexible, allowing new components to be added without regressing other areas and then we went into some performance guidelines and best practises. Only a few minutes were spent discussing the storage they have today. A lot of Clariion, and EMC were pitching DMX as a solution for ongoing growth, but the workloads involved had nowhere near the performance requirements a monolith can provide (from any vendor) – hence why IBM won the bid last year with SVC and some DS4700 storage (which he commented was performing amazingly well for a mid-range controller at that price – but then I guess it depends on where you are coming from) The growth (as we all know) is ongoing, and especially so for the type of data this customer is storing, but he commented that the days of buying anything like a DMX or DS8000 are long gone for them, and SVC with whoever’s mid-range controllers were offering the best price/performance/capacity as they grow in the future were they way forward.

This is truly commoditisation at work, not only reducing the cost of the raw TB used, but enabling an open and wide choice of future purchases for the “commodity” that is storage.