Storage

Watching the Spectralogic announcements from a far and getting involved in a conversation about tape on Twitter has really brought home the ambivalent relationship I have with tape; it is a huge part of my professional life but if it could be removed my environment, I’d be more than happy.

Ragging on the tape vendors does at times feel like kicking a kitten but ultimately tape sucks as a medium; it’s fundamental problem is that it is a sequential medium in a random world.

If you are happy to write your data away and only ever access it in truly predictable fashions; it is potentially fantastic but unfortunately much of business is not like this. People talk about tape as being the best possible medium for cold storage and that is true, as long as you never want to thaw large quantities quickly. If you only ever want to thaw a small amount and in relatively predictable manner; you’ll be fine with tape. Well, in the short term anyway.

And getting IT to look at an horizon which more than one refresh generation away is extremely tough.

Of course, replacing tape with disk is not yet economic over the short-term views that we generally take; the cost of disk is still high when compared to tape; disk’s environmental footprint is still pretty poor when compared to tape and from a sheer density point of view, tape still has a huge way to go…even if we start factor in upcoming technologies such as shingled disks.

So for long-term archives; disk will continue to struggle against tape…however does that means we are doomed to live with tape for years to come? Well SSDs are going to take 5-7 years to hit parity with disk prices; which means that they are not going to hit parity with tape for some time.

Yet I think the logical long-term replacement for tape at present is SSDs in some form or another; I fully expect the Facebooks and the Googles of this world to start to look at the ways of building mass archives on SSD in an economic fashion. They have massive data requirements and as they grow to maturity as businesses; the age of that data is increasing…their users do very little in the way of curation, so that data is going to grow forever and it probably has fairly random access patterns.

You don’t know when someone is going to start going through someone’s pictures, videos and timelines; so that cold data could warm pretty quickly.  So having to recall it from tape is not going to be fun; the contention issues for starters and unless you come up with ways of colocating all of an individual’s data on a single tape; a simple trawl could send a tape-robot into melt down. Now perhaps you could do some big data analytics and start recalling data based on timelines; employ a bunch of actuaries to analyse the data and recall data based on actuarial analysis.

The various news organisations already do this to a certain extent and have obits prepared for most major world figures. But this would be at another scale entirely.

So funnily enough…tape, the medium that wouldn’t die could be kiboshed by death. And if the hyper-scale companies can come up with an economic model which replaces tape…I’ll raise a glass to good time and mourn it little..

And with that cheerful note…I’ll close..

I know people think that storagebods are often backward thinking and hidebound by tradition and there is some truth in that. But the reality is that we can’t afford to carry on like this; demands are such that we should grasp anything which makes our lives easier.

However we need some help both with tools and education; in fact we could do with some radical thinking as well; some moves which allow us to break with the past. In fact what I am going to suggest almost negates my previous blog entry here but not entirely.

The LUN must die, die, die….I cannot tell you how much I loathe the LUN as a abstraction now; the continued existence of the LUN offends mine eyes! Why?

Because it allows people to carry on asking for stupid things like multiple 9 gigabyte LUNs for databases and the likes. When we are dealing with terabyte+ databases; this is plain stupid. It also encourage people to believe that they can do a better job of laying out an array than an automated process.

We need to move to a more service oriented provisioning model; where we provision capacity and ask for a IOPS and latency profile appropriate to the service provision. Let the computers work it all out.

This has significant ease of management and removes what has become a fairly pointless abstraction from the world. It means it easier to configure replication, data-protection, snaps and clones and the like. It means that growing an environment becomes simpler as well.

It would make the block world feel at closer to the file world. Actually, it may even allow us to wrap a workload into something which feels like an object; a super-big-object but still an object.

We move to a world where applications can request space programmatically if required.

As we start to move away from an infrastructure which is dominated by the traditional RAID architectures; this makes more sense than the current LUN abstraction.

If I already had one of these forward-looking architectures, say XIV or 3PAR; I’d look at ways of baking this in now..this should be relatively easy for them, certainly a lot easier than some of the more legacy architectures out there. But even the long-in-the-tooth and tired architectures such as VMAX should be able to be provisioned like that.

And then what we need is vendors to push this as the standard for provisioning…yes, you can still do it the old way but it is slower and may well be less performant.

Once you’ve done that….perhaps we can have a serious look at Target Driven Zoning; if you want to move to a Software Defined Data-Centre; enhancements to the existing protocols like this are absolutely key.