multiple instances of rotatelogs writing to the same file

Hello all,

I have several virtual hosts piping their log files to rotatelogs. For various reasons I have two virtual hosts piping to the same log file:

CustomLog "|/usr/sbin/rotatelogs /logs/site/access_log.%U-%Y 604800" combined


CustomLog "|/usr/sbin/rotatelogs /logs/site/access_log.%U-%Y 604800" combined


In this case there are understandably two processes of rotatelogs running:
..../usr/sbin/rotatelogs /logs/access_log.%U-%Y 604800
..../usr/sbin/rotatelogs /logs/access_log.%U-%Y 604800

Is this setup going to cause any unintended consequences? I'm thinking it might run into a couple of problems but the man page and the web doesn't have a real answer. Does apache and rotatelogs handle cleanly the rotation because there are two processes trying to do the rotation? Is there a file locking problem with rotatelogs whereby one process won't be able to write to the log file?




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Re: multiple instances of rotatelogs writing to thesame file

On 2010-03-09 at 11:03, stupidmail4me wrote:

> Hello all,
>
> I have several virtual hosts piping their log files to rotatelogs. For various reasons I have two virtual hosts piping to the same log file:
>
> CustomLog "|/usr/sbin/rotatelogs /logs/site/access_log.%U-%Y 604800" combined
>
>
> CustomLog "|/usr/sbin/rotatelogs /logs/site/access_log.%U-%Y 604800" combined
>
>
> In this case there are understandably two processes of rotatelogs running:
> .../usr/sbin/rotatelogs /logs/access_log.%U-%Y 604800
> .../usr/sbin/rotatelogs /logs/access_log.%U-%Y 604800
>
> Is this setup going to cause any unintended consequences?

Yes.

> I'm thinking it might run into a couple of problems but the man page
> and the web doesn't have a real answer.

Well, if the doc tried to list all the things people might try that
wouldn't work, it would get awfully long. Nevertheless, if you look at
you'll see this:

Multiple running instances of rotatelogs attempting to rotate the
same logfiles at the same time may destroy each other's logfiles.

Dan

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Re: multiple instances of rotatelogs writing to the

On Tue, Mar 9, 2010 at 9:33 PM, stupidmail4me wro=
te:
>
> Hello all,
>
> I have several virtual hosts piping their log files to rotatelogs. For va=
rious reasons I have two virtual hosts piping to the same log file:
>
> CustomLog "|/usr/sbin/rotatelogs /logs/site/access_log.%U-%Y 604800" comb=
ined
>
>
> CustomLog "|/usr/sbin/rotatelogs /logs/site/access_log.%U-%Y 604800" comb=
ined
>
>
> In this case there are understandably two processes of rotatelogs running=
:
> .../usr/sbin/rotatelogs /logs/access_log.%U-%Y 604800
> .../usr/sbin/rotatelogs /logs/access_log.%U-%Y 604800
>
> Is this setup going to cause any unintended consequences? I'm thinking it=
might run into a couple of problems but the man page and the web doesn't h=
ave a real answer. Does apache and rotatelogs handle cleanly the rotation b=
ecause there are two processes trying to do the rotation? Is there a file l=
ocking problem with rotatelogs whereby one process won't be able to write t=
o the log file?
>
>
>
>
> ------------------------------------------------------------ ---------
> The official User-To-User support forum of the Apache HTTP Server Project=
..
> See for more info.
> To unsubscribe, e-mail: users-unsubscribe@httpd.apache.org
> =A0 " =A0 from the digest: users-digest-unsubscribe@httpd.apache.org
> For additional commands, e-mail: users-help@httpd.apache.org
>

Use standard logging methods, and run logrotate regularly using cron.
I do it this way. With logrotate you can also mail the owner(s) of the
virtualhosts a compressed version of the log for analysis and delete
it from your server.

--
Nilesh Govindarajan
Site & Server Administrator
www.itech7.com

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