Re: "Leaking" disk space on FreeBSD servers

From: Achilleas Mantzios <achill(at)matrix(dot)gatewaynet(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: "Leaking" disk space on FreeBSD servers
Date: 2013-03-20 13:33:41
Message-ID: 5916854.4XXidRi1mn@smadev.internal.net
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On Τετ 20 Μαρ 2013 12:47:39 Dan Thomas wrote:
> > Did you do a detailed du during the supposed problem and after the reboot and make a diff of those to fimd any invlolved files/dirs?
>
> du doesn't show the space in question (du -s shows the actual usage on
> disk, df is showing a much higher number), so I doubt this will show
> anything up. However, next reboot I'll certainly do that.

du (without -s) shows the whole hierarchy, du -s behaves like du -d 0,
so at this point diff the output of (plain) su is definitely somth worth doing.

>
> > That said, i think you might consider posting on freebsd-[questions|stable] as well.
>
> Yes I think that might be a good plan :)
>
> Dan
>
> On 20 March 2013 12:30, Achilleas Mantzios <achill(at)matrix(dot)gatewaynet(dot)com> wrote:
> > Did you do a detailed du during the supposed problem and after the reboot
> > and make a diff of those
> >
> > to fimd any invlolved files/dirs?
> >
> > That said, i think you might consider posting on freebsd-[questions|stable]
> > as well.
> >
> >
> >
> > On Τετ 20 Μαρ 2013 11:49:07 Dan Thomas wrote:
> >
> > Hi Guys,
> >
> > We're seeing a problem with some of our FreeBSD/PostgreSQL servers "leaking"
> > quite significant amounts of disk space:
> >
> > > df -h /usr/local/pgsql/
> > Filesystem Size Used Avail Capacity Mounted on
> > /dev/mfid1s1d 1.1T 772G 222G 78% /usr/local/pgsql
> >
> > > du -sh /usr/local/pgsql/
> > 741G /usr/local/pgsql/
> >
> > Stopping Postgres doesn't fix it, but rebooting does which points at the OS
> > rather than PG to me. However, the leak is only apparent in the dedicated
> > pgsql partition, and only on our database servers, so PostgreSQL seems to at
> > least be involved. The partition itself is a relatively standard UFS
> > partition:
> >
> >
> > > grep /usr/local/pgsql /etc/fstab
> > /dev/mfid1s1d /usr/local/pgsql ufs rw 2 2
> >
> > > tunefs -p /usr/local/pgsql/
> > tunefs: POSIX.1e ACLs: (-a) disabled
> > tunefs: NFSv4 ACLs: (-N) disabled
> > tunefs: MAC multilabel: (-l) disabled
> > tunefs: soft updates: (-n) enabled
> > tunefs: gjournal: (-J) disabled
> > tunefs: trim: (-t) disabled
> > tunefs: maximum blocks per file in a cylinder group: (-e) 2048
> > tunefs: average file size: (-f) 16384
> > tunefs: average number of files in a directory: (-s) 64
> > tunefs: minimum percentage of free space: (-m) 8%
> > tunefs: optimization preference: (-o) time
> > tunefs: volume label: (-L)
> >
> > LSOF isn't showing any open files:
> >
> > > lsof +L /usr/local/pgsql/ | awk '{ print $8 }' | grep 0 | wc -l
> > 0
> >
> > We're not creating filesystem snapshots:
> >
> > > find /usr/local/pgsql/ -flags snapshot
> > >
> >
> > Not all of our servers are leaking space, it's only the more
> > recently-installed systems. Here's a quick breakdown of versions:
> >
> > FreeBSD PostgreSQL Leaking?
> > 8.0 8.4.4 no
> > 8.2 9.0.4 no
> > 8.3 9.1.4 yes
> > 8.3 9.2.3 yes
> > 9.1 9.2.3 yes
> >
> > Each of these servers is configured with a warm standby, so we've been
> > switching them over to the standby to reclaim the space (rebooting the
> > primary is too much downtime). The standby does *not* demonstrate this
> > problem while it's being used as a standby, but it starts leaking space once
> > it's been made the primary.
> >
> > Initially I thought this might be related to WAL files, however the pg_xlog
> > dir is symlinked outside of the /usr/local/pgsql partition that is
> > demonstrating this problem:
> >
> > > ll /usr/local/pgsql/data/pg_xlog
> > lrwxr-xr-x 25B Oct 19 10:48 pg_xlog -> /usr/local/pglog/pg_xlog/
> >
> > I've exhausted everything I can think of to try to solve this one. Has
> > anyone got any ideas on how to go about debugging this?
> >
> > Thanks,
> >
> > Dan
> >
> >
> >
> > -
> >
> > Achilleas Mantzios
> >
> > IT DEV
> >
> > IT DEPT
> >
> > Dynacom Tankers Mgmt
>
>
>
-
Achilleas Mantzios
IT DEV
IT DEPT
Dynacom Tankers Mgmt

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