Performance benchmarks with the latest internal release (0.8.0)  show that the read/write performance of Dispersed Storage went up by 2x (again!).  We're now generally seeing realized throughput rates in the 20-30 MBps range (equal to 160-320 Mpbs) though a single Accesser (client) on a dsNet.  This level of performance is well beyond the theoretical maximum that we thought we'd get to in this initial release.  (So it is a good thing that our developers are better at performance improvements than they predicting the theotical maximum for performance!)

To put that in perspective, we ran some apple-to-apples comparisons between a dsNet and a local hard drive.  The test we ran was reading and writing a 1 GB file on both a local (desktop PC) hard drive and a dsNet over a 1 Gbps connection.  It turns out that the dsNet was a bit faster for the write and a bit slower for the the read vs. a local hard drive.  The results are in this chart:

Overall, this is a huge deal.  This level of performance is about 100x where we thought we'd end up for this release.  Because we are now providing hard drive level performance through regular hard drive interfaces (Block, iSCSI, etc.), we really are optomisic about the potential for Dispersed Storage.

Going forward, we are confident that we'll be able to increase the performance of dsNets even further and ultimately consistently exceed hard drive performance.

Chris

In preparing a presentation recently on long term trends in data storage, I was talking with Russ Kennedy and he mentioned that it was a known fact within the data storage industry that hard drive performance has been lagging.  So mentioned this to Dennis Roberson and he connected me with this article at Tom’s Hardware which I found very enlightening.

It turns out that increases in hard drive capacities have been keeping pace with Moore’s law (as observed) by doubling every 24 months.  But hard drive performance (reads and writes) hasn’t been keeping pace.  Even though hard drive performance has been increasing, it hasn’t been increasing as fast as hard drive capacities have been increasing. 

So if the amount of data that people want to read from and write to hard drives has been increasing with the rate of increase of CPU performance and hard drive capacities, then the realized performance of hard drives (on this “technology adjusted” basis) has been getting SLOWER!  This is a big part of why Windows never seems to load any faster.

The article at Tom’s Hardware really brought these diverging trends together in a compelling way by measuring the speed to read a single platter against the year when the hard drive was manufactured.  This chart shows that the speed to read a single platter of data has decreased by almost 10X over the past 15 years.  Wow. 

If these trends continue, hard drive speeds will become an increasingly limiting factor which will further limit the approach of a local hard drive as the primary data storage system.  Especially for high performance environments, the solution to lagging drive performance will be architectures like Dispersed Storage that write to or read from multiple drives in parallel.

Chris