I agree 1GB is a lot, I played around with that value, but it hardly makes a difference. Is there a plateau in how that value affects query performance ? On a master DB, I would set it low and raise as necessary, but what would be a good average value on a read-only DB with same spec and max_connections ?
I will run a test again and let you know how is the IO. Might also run bonnie++ to see if the raid performs as expected...
Sébastien
On Wed, Sep 12, 2012 at 6:17 PM, François Beausoleil
<francois@teksol.info> wrote:
Le 2012-09-12 à 17:08, Sébastien Lorion a écrit :
> As you can see, I am nowhere near the results John mentioned for a 10,000 scale (about 8000 tps) and I am not sure why. My instance setup and configuration should be ok, but I am far from an expert (a startup founder has to wear many hats...), I simply followed advice found in Greg Smith book and what I read on the net. So, if anyone can offer insight as to why the performance is not as good as expected, please let me know ..
>
> I did not terminate the AMI yet, so I can do more testing and/or try suggestions to improve the results. I will also try to run the benchmarks again on a pure RAID1 configuration with fsync off, which I will use for read-only databases.
I wonder if work_mem is too high? That's 1 GB per connection (max), but still a lot of RAM. Might want to try with more reasonable values, such as 16MB to 64MB.
What are the iostat / vmstat numbers during the test?
Bye,
François
