Online and offline storage: cost and greenness at Sun PASIG

I was at the Sun Preservation and Archiving SIG meeting in Malta a couple of weeks ago, a very interesting meeting indeed. The agenda and presentations are being mounted here. I’ll try to pick out some points that are worth briefly blogging about, if I can.

Raymond Clarke of Sun and SNIA spoke quite early on about storage (presentation not up yet). You may know that Sun now holds the Internet Archive, apparently in a mobile data centre (basically a standard container in a car park!). The point I was interested in was Raymond’s comments about tape, which he said was the fastest growing market segment. He said the cost ratio of disk:tape storage was 23:1. But, noting that storage represents around 40% of the power consumption of data centres, and given our current environmental concerns, it’s notable that the energy ratio for disk:tape is 200:1!

On risk, a separate presentation by Moreira (pdf) also spoke about the green and cost advantages of tape (although he only identified a 3:1 advantage), but I note two tweets from the time:

dkeats: Tapes degrade, data loss happens, there is risk, need to measure quality of tapes in real time, and manage risk. #pasig

cardcc: #pasig Moreira shows green & cost advantages of tape, but concerns on fragility & lifetime 5-10-30 years, but maybe only days if mistreated

Now there was an element of standard vendor pitch towards hierarchical storage management systems. But if you have very large volumes, sufficient value but relatively low re-use rate, then despite some of the significant disadvantages of tape, those numbers have to drive you towards a tape solution for preservation and archiving! It certainly will significantly increase the up-front investment cost, the data centre management requirements, and possibly some risk factors, but given sufficient volumes you should make savings overall. And this could apply to quite a bit of research data...