Interviews

posted on 23 June 2008 11:28

Hitachi Data Systems (HDS) is introducing solid state drives (SSDs) into its offering. We had a talk with Bob Plumridge, Technical Marketing Director for Hitachi Data Systems (HDS) in Europe, and asked several questions about developments like this affecting HDS and its customers.

B&F: What is HDS' attitude towards 2.5-inch drives?

Bob Plumridge: Right now we don't ship any 2.5-inch drives. I agree that 2.5-inch drives do seem to be the future. The capacities are inceasing rapidly. They provide the ability to get more drives into a footprint ... 2.5-inch drives will help with space constraints.

But it's not just a case of putting more drives in a space. One of the problems is heat. Supose you have 600 - 700 drives in the same floorspace as 500 3.5-inch drives? Each drive puts out about the same amount of heat which has to be dissipated. How do you do that? Do we water-cool the racks?

Reliability is another thing. There's potentially 100s of terabytes in one frame. If you lose access to that frame the impact is likely to be catastrophic. ... It's all about getting the advantages without affecting reliability and availability.

B&F: Suppose we added deduplication in the controller and replicated the frames's contents?

Bob Plumridge: A remote copy to a DR site is one solution. But users would be copying hundreds of terabytes between sites. Deduplication is an answer, which we do by partnering.

Yes (deduplication in the controller) is being discussed. It's something that's seriously being looked at for all sorts of reasons. If you could even do 10:1 deduplication with hundreds of terabytes you're talking massive reductions in drive numbers and floor space, etc.

It's not the same I/O rate with deduplication. None of the deduplication vendors could support thousands of servers connected to one storage device. Imagine 2,500 servers connected to one storage device; deduplicating that can't be done.

(Also) it's got to be absolutely rock-solid. We're talking now about deduping backup data. If you move dedupe into the main storage and that goes wrong you have lost your primary data. ... The possible consequences (of it going wrong) are unimaginable. The reputation of the company would disappear overnight.

B&F: Is mixed SAS and SATA storage coming?

Bob Plumridge: Yes; in the future mixed mode SAS and SATA storage is coming; I guess in the near future.

B&F: What about HDS and solid state drives?

Bob Plumridge: SSDs provide extra performance, moving towards instant access. We are going to support SDs and there are two suppliers in the frame. I'm not allowed to say who they are.  We're dual-sourcing - which is pretty standard across the industry.

It's nothing new (though), we did it many years ago with solid state on mainframes. SSD is another notch up in terms of performance. The technology is not without its issues; the wear rate is absolutely an issue; they will degrade in time as hard drives do and will need replacing as hard drives do.

People will use SSDs for special applications. We won't see hundreds of terabytes of it.

B&F: For HDS the reliability and dependability of its storage products are paramount. We may conclude that adding deduplication to its controllers for primary storage applications is quite unlikely to happen, even impossible to imagine. The position with regard to a controller of an array for backup data could be different though.

We may imagine that HDS will introduce trays of 2.5-inch drives to its product range once the reliability and heat issues mentioned above have been solved. The arrival of SSD trays and the mixing of SAS and SATA drives at the 3.5-inch level are both a done deal.

^{[Chris Mellor.]}