From: Scott Marlowe <scott.marlowe@gmail.com>
To: david@lang.hm
Cc: Scott Carey <scott@richrelevance.com>
Cc: James Mansion <james@mansionfamily.plus.com>
Cc: Greg Smith <gsmith@gregsmith.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Effects of setting linux block device readahead size
Date: Thu, 11 Sep 2008 20:30:38 -0600
Message-ID: <dcc563d10809111930g10fc5256wac2020d596e3474d@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.1.10.0809111529120.15169@asgard.lang.hm>
References: <70c01d1d0809092353r4ae687a3ycf3d99d43a5680cf@mail.gmail.com>
<a1ec7d000809100926w28a4a57dy7c13f2942edc57ff@mail.gmail.com>
<Pine.GSO.4.64.0809101313070.4714@westnet.com>
<48C8AACD.5090702@mansionfamily.plus.com>
<Pine.GSO.4.64.0809110150070.3993@westnet.com>
<48C97793.2070909@mansionfamily.plus.com>
<a1ec7d000809111336m8027c74u62c9a3567ee7301f@mail.gmail.com>
<alpine.DEB.1.10.0809111434240.15169@asgard.lang.hm>
<dcc563d10809111440q414c5285j5bff925fad310b41@mail.gmail.com>
<alpine.DEB.1.10.0809111529120.15169@asgard.lang.hm>
On Thu, Sep 11, 2008 at 4:33 PM, <david@lang.hm> wrote:
> On Thu, 11 Sep 2008, Scott Marlowe wrote:
>
>> On Thu, Sep 11, 2008 at 3:36 PM, <david@lang.hm> wrote:
>>>
>>> by even if it didn't, most modern drives read the entire cylinder into
>>> their
>>> buffer so any additional requests to the drive will be satisfied from
>>> this
>>> buffer and not have to wait for the disk itself.
>>
>> Generally speaking I agree, but I would still make a separate logical
>> partition for pg_xlog so that if the OS fills up the /var/log dir or
>> something, it doesn't impact the db.
>
> this is a completely different discussion :-)
>
> while I agree with you in theory, in practice I've seen multiple partitions
> cause far more problems than they have prevented (due to the partitions
> ending up not being large enough and having to be resized after they fill
> up, etc) so I tend to go in the direction of a few large partitions.
I've never had that problem. I've always made the big enough. I
can't imagine building a server where /var/log shared space with my
db. It's not like every root level dir gets its own partition, but
seriously, logs should never go anywhere that another application is
writing to.
> the only reason I do multiple partitions (besides when the hardware or
> performance considerations require it) is when I can identify that there is
> some data that I would not want to touch on a OS upgrade. I try to make it
> so that an OS upgrade can wipe the OS partitions if nessasary.
it's quite handy to have /home on a separate partition I agree. But
on most servers /home should be empty. A few others like /opt or
/usr/local I tend to make a separate one for the reasons you mention
as well.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: scott.marlowe@gmail.com, david@lang.hm, scott@richrelevance.com, james@mansionfamily.plus.com, gsmith@gregsmith.com
Subject: Re: Effects of setting linux block device readahead size
In-Reply-To: <dcc563d10809111930g10fc5256wac2020d596e3474d@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox