Re: Running PostgreSQL with ZFS ZIL

On Thu, Jul 2, 2015 at 11:50 AM, Vick Khera <vivek(at)khera(dot)org> wrote:

>
> On Thu, Jul 2, 2015 at 10:56 AM, Joseph Kregloh <jkregloh(at)sproutloud(dot)com>
> wrote:
>
>> With my dataset I have been able to take advantage of the L2ARC.
>> Currently using about 80GB on ARC and 260GB on L2ARC. With the ARC
>> currently having the greater Hit ratio.
>>
>
> Did you tell postgres that the effective_cache_size = Shared Buffers +
> ARC? I don't include in postgres the L2ARC size as it is not really in
> memory. Also, I lie to postgres about the random_page_cost
> and seq_page_cost and set them both to 0.3 since there is so much cached.
>

In my current test config, I set the effective_cache_size to half the
available ram, so roughly 50GBs. I have not tweaked the random_page_cost or
seq_page_cost yet.

> Set full_page_writes = off since ZFS already takes care of that for you,
> too.
>

I currently have the full_page_writes on. I'll disable it and test.

Thanks,
-Joseph Kregloh