On Wed, Jul 6, 2016 at 12:13 PM, Merlin Moncure <mmoncure@gmail.com> wrote:
> Disabling write back cache for write heavy database loads will will
> destroy it in short order due to write amplication and will generally
> cause it to underperform hard drives in my experience.
Interesting. We found our best performance with a RAID-5 of 10 800GB
SSDs (Intel 3500/3700 series) that we got MUCH faster performance with
all write caching turned off on our LSI MEgaRAID controllers. We went
from 3 to 4ktps to 15 to 18ktps. And after a year of hard use we still
show ~90% life left (these machines handle thousands of writes per
second in real use) It could be that the caching was getting in the
way of RAID calcs or some other issue. With RAID-1 I have no clue what
the performance will be with write cache on or off.
--
To understand recursion, one must first understand recursion.