Friday, 25 May 2007

Mine's Bigger than yours - Part Deux

Old Barry's at it again with the DMX pitch, this time for VTL.

Here's a quick comparison with Copan's Revolution 220TX system and the specification of the DL6100 from EMC's website.

Copan Revolution 220TX

  • Single Cabinet
  • 896 drives (500GB SATA)
  • Power (max): 6368 watts
  • Throughput: 5.2TB/hour
  • Capacity: 448TB max
  • Emulation: 56 libraries, 56 drives, 8192 virtual cartridges

EMC DL6000

  • 7 cabinets (max configuration)
  • 1440 drives (500GB LCFC)
  • Power (max): 49100 watts
  • Throughput: 6.4TB/hour
  • Capacity: 615TB max
  • Emulation: 256 libraries, 2048 drives, 128000 virtual cartridges

So, you'd need 1.5 Copan devices to match the EMC kit and yes, it doesn't scale as well in terms of virtual components, but there are some big issues here. For instance, EMC's device isn't green - the power demands are huge and not surprising, as the drives are all spinning all the time (Copan have only 25% max if theirs in use at any time). Floor density is not good in the DMX - why? Because the drives are in use all the time and it is an Enterprise array, so timely replacement of disk failures is important - but less so for a virtual tape system which can tolerate downtime.

So what would you go for? My money would be on a DMX for Enterprise work, which it is great at - and not as a "one size fits all" system, which it quite plainly is not.


the storage anarchist said...

Mine's still bigger :)

Seriously: I'm curious to know if you'd feel any differently if the DL6000 could also power down unused drives? How about if we also removed all the extra standby power supplies (& batteries)?

Chris M Evans said...

Barry, possibly, but it would also depend on cost. I don't see why I need to pay DMX price for data which is 90% inactive. I do like DMX and I think it's a great system for OLTP constantly accessed data but not as a VTL.

Stephen said...

I just found this site. We have purchased two Copans mainly for the VTL but we are looking at the archiving option also.

We were very keen on the green aspect of the Copan. The only real problem we have found is that the floor rating is not quite standard. 1.25 tonnes per square metre which is not really what our floor can handle and the power is a bit odd.

They are BIG heavy systems and much denser in storage compared to our USP's. The Stotek VTL's we have are toys when you look at both of them.

Quite simply, we are looking at doing cross data center replication as a test and then if all goes well, we might even ditch our tape libraries in the next year or two and just have the Copans. I think the Copans offer a good solution to disaster recovery/business continuity if they perform as well as they say.

I have used SAMFS as an archiving solution on Solaris and found it annoying at best as it was not really a good archiving solution.

Hopefully, after some experimentation I will be able to comment fully on how good the Copans are.

Time will tell with these systems.


Chris M Evans said...

Stephen, that would be interesting, I look forward to hearing about it...