Original URL: http://www.theregister.co.uk/2011/01/07/interpreting_xiotech_ise_controller_strategy/

Tech veep denies Xiotech ISE controller strategy change

'It's certainly possible'

By Chris Mellor

Posted in Storage, 7th January 2011 15:50 GMT

Comment Rob Peglar, Xiotech's VP for technology, took issue with some aspects of the story about the ISE NAS Controller Node.

He told the Reg:

The basic clarification is this: ISE NAS today is exactly the same strategy as it was back in April.  We have changed high-stack technology, from Symantec Filestore to Windows 2008 Storage Server, true.  However, your statement about ‘FC block access’ is misleading.

We do indeed offer FC block access as part of ISE NAS – without question, it’s a unified storage offering – but the FC traffic does not pass through the NAS head.  It goes directly to ISE.  The NAS head does support iSCSI target, but that is a software target (as part of Storage Server) and the actual block I/O is FC, from the head to the ISE.

Overall, the head does adhere to our philosophy of providing high-stack function in efficient engines – riding the CPU wave as it were – and low-stack, highly optimised, highly efficient, high-performance storage function in the ISE.

As for the Emprise line, that continues in the form of the Emprise 9000 – you do know about that, right?  The article only referenced the 7000, which is ISE-based (of course) but does not offer the wide portfolio of high-stack function that the 9000 does.  The 9000 is an interesting machine because like its brother ISE NAS, it too provides FC block function, but in two ways; either through the 9000 head itself, or directly from server to ISE.  Both are allowed, which is a unique method compared to other enterprise storage arrays which force all FC traffic through the controllers.

You wished for an upscale 7000 – the 9000 is it. 8Gbit/s, 4 or 8 ports per controller, clustered controllers up to 12 (sold in pairs), 96 ISEs behind it, 10Gb Ethernet iSCSI, and on and on.  A truly enterprise-class machine, unlike the 7000, which ventures up into the high mid-tier but not beyond, as it is limited to two controllers.

We had covered the Emprise 9000 when it was introduced. I thought Rob's note explained a lot and it got me thinking.

My general understanding about Xiotech's storage controller thinking is in line with Rob's but has an added couple of aspects. One is/was that Xiotech had no real interest in building and supplying software and hardware to run upper stack storage management functions, which would execute in server hardware not supplied by Xiotech and which would be physically separate from the storage array enclosures, the ISEs. Software such as Symantec's File Store would provide the functionality to do that work and it could run in any vanilla X86 controller with sufficient horsepower.

Peglar said about this:

This is mostly correct. However, Xiotech did indeed supply the actual hardware, because customers prefer it that way. They wanted a solution, so we packaged FileStore on a server (Dell or HP, customers’ choice). If the customer wanted to run FileStore on their own x86 hardware, they could, but they would procure FileStore from Symantec directly in that case, and run it with ISE.

Xiotech supplying controller software

Now, with the ISE NAS Controller Node, Xiotech is supplying the software, albeit OEM'd from Microsoft, and, maybe, with Xiotech's own SW additions, and is also supplying the hardware, the 1U box. Rob points out that this is no different from the Emprise 9000 in several ways but I think I see that differently. The Emprise 9000 was, I thought, a legacy approach.

With the ISE NAS Controller Node, I believe that Xiotech is not getting away from supplying controller hardware at all. It is supplying an access controller (Emprise 9000) with FC pass-through and FC-direct access to the ISEs, and it is supplying the unified storage NAS Controller, both HW and SW, with NAS and iSCSI block access through the controller and FC direct access to the ISE enclosures.

Peglar's response:

Again, that is true, but it is because our customers want it that way. They don’t want to procure servers separately to run the high-stack function, and then worry about the support from a different vendor. We find most customers prefer an integrated, one-throat-to-choke approach... This differs greatly from what we did with legacy systems such as the original Magnitude, where every bit of hardware was of our own design and manufacture.

High-stack function in efficient engines

All this leads me to think that we might well see an Emprise 9000 refresh with NAS head functionality added to it, so providing a 2-level unified storage product range. If I were in Xiotech product management that's what I would be strongly arguing for. I'd be saying that Katana-enhanced ISEs with an ISE NAS Controller'ised Emprise 9000 and existing ISE NAS Controller would provide a powerful pair of products that could compete well against other storage arrays.

But hey, I'm not in product management...

Rob wrote that Xiotech has a "philosophy of providing high-stack function in efficient engines". To my mind this is not that different from NetApp, EMC, HP, et al, apart from Xiotech's division of storage management function between high-stack stuff in the controller and low-stack operations into the ISEs. In effect, it now has a distributed storage controller function and could, and possibly will, have the high stack functions running as Xiotech software in a virtual machine and talking to the ISEs. In my opinion you could do that now with the ISE NAS Controller Node software.

Rob Peglar's parting shot here is this: "You could indeed, but at the cost of traversing the virtual-physical translation layer, which would reduce I/O performance. However, to your point, it’s certainly possible." ®