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References: <54E5385D47A89542BC678F5426799F3904961EF60F@OSTIEX01.osti.gov>
Date: Tue, 2 Mar 2010 12:20:10 -0700
Message-ID: <dcc563d11003021120u2cc0ec95ud8802126521e442c@mail.gmail.com>
Subject: Re: The OS Command for pg_hotbackup -- Use lvmsnapshot
	instead of tar cvzf
From: Scott Marlowe <scott.marlowe@gmail.com>
To: "Arnold, Sandra" <ArnoldS@osti.gov>
Cc: "pgsql-general@postgresql.org" <pgsql-general@postgresql.org>,
	"pgsql-admin@postgresql.org" <pgsql-admin@postgresql.org>
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On Tue, Mar 2, 2010 at 8:43 AM, Arnold, Sandra <ArnoldS@osti.gov> wrote:
> I am currently using the pg_hotbackup Perl script to backup my production
> PostgreSQL database.=A0 However, the next production database is going to=
 be
> close to a terrabyte in size.=A0 We feel that a tar cvzf command is not t=
he
> correct OS backup solution to use.=A0 Instead we would like to use
> lvmsnapshot.=A0 Is anyone using the pg_hotbackup script but instead of=A0=
the tar
> cvzf OS command are they using lvmsnapshot?
>
> Or, is anyone using lvmsnapshot and doing point-in-time recoveries?

I do not run my databases on LVM because, at least in the past, LVM
did not properly honor fsync / write barrier commands.  I don't know
if this has since  been fixed.   If your transaction rate on LVM is
unnaturally higher than it should / could be, then suspect it is not
fsyncing, and putting your data on it is putting it at risk.