> And those two layers in the middle are already providing a significant
> speedup on burst workloads. Ultimately, all the burst stuff has to make
> it onto regular disks eventually though, if you can't fit the whole
> thing on SSD, and then you're back to solving the non-SSD problem
> again. That's the problem with these things that keeps them from being
> magic bullets; if you have a database large enough that you can't fit
> the working set in RAM nowadays, you probably can't fit whole thing on
> SSD either.
The only times we've seen real gains from using SSD's in production was
when we lavished money on a lot of them for data warehousing. There the
speedup in both throughput and random seeks really boosted performance.In the other use cases I've tested, the only
realadvantage to SSDs was
keeping your form factor down.
I haven't been able to test things like putting a "hot" table on a
specific SSD.
-- -- Josh Berkus PostgreSQL Experts Inc.
http://www.pgexperts.com