Re: tar, but not gnu tar

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Tena Sakai <tsakai(at)gallo(dot)ucsf(dot)edu>
Cc: pgsql-admin(at)postgresql(dot)org
Subject: Re: tar, but not gnu tar
Date: 2007-08-22 01:33:34
Message-ID: 200708220133.l7M1XYt15860@momjian.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-admin

Tena Sakai wrote:
> Hi Everybody,
>
> According to section 23.3.2 of 8.2.4 manual:
>
> Also, some versions of GNU tar consider it
> an error if a file is changed while tar is
> copying it. There does not seem to be any
> very convenient way to distinguish this
> error from other types of errors, other
> than manual inspection of tar's messages.
> GNU tar is therefore not the best tool for
> making base backups.
>
> On my linux machine, gnu tar is the tar. Does
> anybody have a suggestion as to where I can go
> to get a tar that is not gnu?

We have updated the 8.3 documentation to be more accurate about GNU tar:

Some backup tools that you might wish to use emit warnings or errors
if the files they are trying to copy change while the copy proceeds.
This situation is normal, and not an error, when taking a base backup
of an active database; so you need to ensure that you can distinguish
complaints of this sort from real errors. For example, some versions
of <application>rsync</> return a separate exit code for
<quote>vanished source files</>, and you can write a driver script to
accept this exit code as a non-error case. Also, some versions of
GNU <application>tar</> consider it an error if a file is changed
while <application>tar</> is copying it. Fortunately, GNU
<application>tar</> versions 1.16 and later exit with <literal>1</>
if files changed during the backup, and <literal>2</> for other errors.

so your version of 'tar' might be fine.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://www.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +

In response to

Browse pgsql-admin by date

  From Date Subject
Next Message Tena Sakai 2007-08-22 01:53:53 Re: tar, but not gnu tar
Previous Message Kevin Grittner 2007-08-22 01:02:38 Re: tar, but not gnu tar