On 30/04/13 11:09, Jason White wrote:
James Harper <james.harper@bendigoit.com.au> wrote:
I'm hoping that ceph with the journal on an SSD will improve my situation somewhat... my SSD's arrive tomorrow.
I found out that to take full advantage of a modern SSD, it is necessary to have a machine with a SATA 3.0 controller capable of a 6 GBPS transfer rate.
this rules out my current desktop and laptop systems.
Not really..
You'll still reap all the benefits of instant seek times and huge iops performance. You just will cap out at ~300mbyte/sec transfers instead of ~600mbyte/sec, but honestly, how often does that matter?
The latency is what I'm going for here. The SSD is only holding the journal so it has the benefits of being able to turn tiny synchronous writes into bigger writes to the rotating media, and while higher SSD throughput would help smooth out the peaks I'm ultimately still limited by the throughput of the rotating media. If I was using the SSD as a cache (bcache/flashcache/etc) then the faster throughput might matter more, but we all have budgets :) James