Re: Block size recommendation for Red Hat Linux 7.2

Stick to 4k linux block size and you should be OK. I've yet to run
into a situation where changing either has made any measurable
difference.

On Mon, Apr 24, 2017 at 11:58 AM, chiru r <chirupg(at)gmail(dot)com> wrote:
> Thanks Scott.
> Please suggest the OS block sizes for Linux redhat 7.2, where as default
> Linux block size is 4k.
>
> If we keep 8k block size at OS level is it improves PostgreSQL performance?
> Please suggest what is the suggestible default OS block size for Linux
> systems to install PostgreSQL.
>
> Thanks,
> Chiru
>
> On Mon, Apr 24, 2017 at 12:29 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
> wrote:
>>
>> On Mon, Apr 24, 2017 at 9:41 AM, chiru r <chirupg(at)gmail(dot)com> wrote:
>> > Hello,
>> >
>> > I am building new server to run PostgreSQL 9.5.4 version on it. Please
>> > provide the recommended Block size for Linux systems.
>> >
>> > We are using PostgreSQL blocks size is 8k default one.
>> >
>> > postgres=# show block_size ;
>> > block_size
>> > ------------
>> > 8192
>> > (1 row)
>> >
>> > Is there any recommendation for separate block sizes on OS level for
>> > Pg_xlog, pg_log and Actual data files to improve the performance for
>> > reads/Writes?.
>>
>> Unless you've done some testing to show some other block size is
>> better, it's best to stick to 8k block size. Keep in mind that while
>> it is configurable at compile time, it doesn't get much testing at
>> other sizes and you could run into corner cases where there are
>> problems and the only acceptable fix is to compile with 8k blocks and
>> reload your whole db etc.
>>
>> tl;dr: Stick to 8k blocks.
>>
>> --
>> To understand recursion, one must first understand recursion.
>
>

--
To understand recursion, one must first understand recursion.