[OpenIndiana-discuss] SSD swap space performance

[Jan Owoc]

On Wed, Aug 8, 2012 at 8:49 AM, Udo Grabowski (IMK)
<udo.grabowski at kit.edu> wrote:
> On 08/08/2012 16:47, Reginald Beardsley wrote:
>>
>> Has anyone done any testing on the performance of an SSD for swap vs disk?
>> I'm currently fully populated at 12 GB in my Z400.
>>
> That should work, but if you really need a fast SSD for
> regularily swapping, you may should start thinking about
> more memory...

I haven't done testing on OpenIndiana, but in my experience swap on an
SSD is an order of magnitude faster than swap on HDD. Note that, as
Udo pointed out, this is still an order of magnitude (or two) slower
than additional RAM.

If your workload is such that you have large chunks of memory that can
be swapped out for extended periods of time, then an SSD will do this
several times faster. However, if you have a program that is actively
using more than the 12GB of RAM you have, you will kill your SSD (SSDs
have a limited number of write cycles - each time you'd run the
program, loads of data would hit the SSD) and won't get anywhere near
the performance of actually having adequate memory.

Jan