Message-ID: <df772cb764b99d4f4a454ee307840022c91bcdb6.camel@cybertec.at>
Subject: Re: IO scheduler recommendation
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: AB_ba# <bharti.anup@gmail.com>, pgsql-admin@lists.postgresql.org
Date: Mon, 21 Jan 2019 16:44:51 +0100
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AB_ba# wrote:
> I searched the complete PostgreSQL Documentation but didn't get anything with respect to IO scheduler recommendation.
> What is being recommended by PostgreSQL ?

There is no clear recommendation.

I personally have seen workloads where changing from "cfq" to "deadline"
or "noop" improved performance by a factor of 4, but on many systems "cfq"
seems to be doing at least as good as the others.

I believe that it depends a lot on your hardware configuration and
your workload, and you are best advised to run a realistic load test.

> Which is the best IO scheduler considering the Data is hosted on NFS?

No idea - probably depends on what is behind the NFS.

Make sure to use hard, fg mounts.
If you can, use "jumbo frames" so that an 8KB block can fit into
a single IP frame.

Yours,
Laurenz Albe
-- 
Cybertec | https://www.cybertec-postgresql.com