ScaleIO uncloaks, offers glimpses of mighty SANitisation plans Startup ScaleIO has come out of stealth-mode operation. Its ECS virtual storage appliance (VSA) is on major steroids, making it a serious alternative to existing storage array network (SAN) arrays rather than a toy. ScaleIO turns application servers' local storage into an on-demand low-cost SAN. This puts it in the same …
I still remember when SAN was first introduced and we were told we didn't need to worry about where we put our data anymore, the SAN would take care of it and guarantee performance......... the results were, to say the least, disappointing.
The sad thing is, here I am today, many years later and at most sites I see the same old problems with SAN performance. A number of sites have gone back to local disks for performance using DB technology like replication to handle availability. I've got to say I can see why. It's easier to get good performance and a lot cheaper.
So, sadly, I'm sceptical that ECS is even worth looking at.
VSA approaches fly in the face of the separation trend, where storage and compute are in different gear. One major weakness that VSA needs to overcome is the complexity of upgrades. In the 'separate' model, replacing stateless server engines is easy, and can be done on a different timescale to the storage farm. Operation with hypervisors is easy, too. A hidden advantage is that diskless servers will have better airflow, and potentially can be run without chillers, saving substantially on energy costs.
The VSA approach requires most servers to be active, though careful zoning of data may mitigate this. Stateless VM systems can, in contrast, power down unused gear, maintaining a float of unused VMs based on predicted demand.
Does VSA have a value-proposition in pre-integrated clusters? Here, all the gear is typically always on, and a VSA approach is intriguing.
To both comments - to the first guy saying people moving to local storage - that makes a lot of sense if you can accurately predict your workload and space requirements up front. Or if you have advanced software running locally that can manage that for you (such as Oracle ASM). MySQL by contrast is absolutely terrible with storage management.
Local storage is of course quite primitive when it comes to distributing data, especially as you grow.. Of course some SAN technologies are crap at managing that as well so the idea is to not use a crap technology:)
Of all the companies I have worked for (all of them startups) - none have been able to accurately predict workloads or requirements. So having a dynamic storage system on a SAN really helped out (vs local storage). A simple software feature change could have a dramatic impact on I/O requirements virtually overnight.
I found it funny that these ScaleIO guys say their software is being tested by, among other things "in memory databases" -- where's the disk I/O need there?
To the second poster talking about upgrades - totally agree there too. The Scale IO "Vision" sounds very nice, but it will take a LOT of deployments and years in production before they can convince me it can work.
Many storage companies have tried to go hardware agnostic over the years, and more often then not they end up abandoning that approach - too many things to support whether it is OS versions, drivers, firmware (even firmware on the underlying disks or SSDs). So many combinations increase the risk for such an endeavour to unacceptable levels for anything beyond the most trivial deployments.
So say they come to their senses and standardize on say a small number of proven configurations - the complexity (and latency) involved with such a grid storage system still has a lot more risk for performance problems and availability problems than a traditional tier 1 storage system for online applications. Now if your talking about tier 2 or tier 3 storage, then of course the requirements aren't as strict.
I think Amazon does something similar with their EBS storage - a grid of servers with iSCSI on them. And it sucks, horribly. S3 is a different beast since it is an object store, your not going to be running a database or other transactional application off of S3.
Don't get me wrong I think the idea of ScaleIO is great, assuming they can get it to work right (for that mainly they need years of time). I don't have confidence they can pull it off though, it's a really complex task to get right.
"The El Reg storage desk asked ScaleIO if it could say where the HP StoreVirtual VSA, the Dell EqualLogic VSA and other specific VSAs fall short" There's no such thing as an Equallogic VSA! There is a 'virtual array' sales and training tool, but it has significant limitations in order to prevent it being run in a production environment, and is available internally at Dell only, or to Tier 1 partners with correct authorisation.
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