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Re: can postgres run well on NFS mounted partitions? - Mailing list pgsql-general

From anj patnaik
Subject Re: can postgres run well on NFS mounted partitions?
Date
Msg-id CAEQKwS=0zQt-uTwxGjFz_0vUw56ND8Mm+8Os-3XuV+WdgMbAbQ@mail.gmail.com
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In response to Re: can postgres run well on NFS mounted partitions?  (Scott Marlowe <scott.marlowe@gmail.com>)
Responses Re: can postgres run well on NFS mounted partitions?
Re: can postgres run well on NFS mounted partitions?
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The Linux VM where postgres is running over NFS is in a different location than where I am. Both the NFS mounted storage and VM are on the same network connected via 1GB ethernet switch.

The physical server for the Linux VM has UPS. 

Is there any specific test I can run to do power failure? 

Can I reboot my VM to test this or that wouldn't be good enough?

Also, why does a checkpoint need to run? I used the graphical installer to install postgres so I assume it would start automatically when the server starts. 

I was also thinking of blackhole testing. If I do a blackhole to the NFS server would I be able to test this accurately?

Folks in the other teams believe NFS should work fine for us so I need to check it out.

Your ideas are  highly appreciated!



On Tue, Nov 10, 2015 at 9:59 PM, Scott Marlowe <scott.marlowe@gmail.com> wrote:
On Tue, Nov 10, 2015 at 4:26 PM, anj patnaik <patna73@gmail.com> wrote:
> Thanks for the feedback. I have setup a second Linux VM (running RHEL 5.11)
> and Postgres 9.4. I ran some insertions today from a client running on
> Windows. The client does a loop of 30 updates.
>
> I am seeing about 10-20% increase in latency in the case where DB is on NFS
> (over TCP) compared to directly on disk.
>
> The other machine I am using to compare is running RHEL 6.5 and Postgres
> 9.4.
>
> Are there any specific tests that are recommended to test that postgres over
> NFS works well?
>
> I am planning on doing a few large data inserts and fetches.
>
> With the little testing, the DB over NFS appears fine.

You need to do a power failure test. While running something like
pgbench for a few minutes, run a checkpoint command and then pull the
plug on the NFS server and / or the pg server. Bring it back up. Is
your db corrupted? Then there's something that needs fixing.

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