[systemd-devel] journal space requirements

[Zbigniew Jędrzejewski-Szmek]

On Thu, Nov 29, 2012 at 10:37:26AM +0000, Colin Guthrie wrote:
> Hi,
> 
> So a couple complaints/queries are beginning trickling in regarding
> journal space requirements.
> 
> A user was complaining that rotated journals were taking up too much
> room and they could be compressed down etc. I did explain that a rotated
> journal is really any different to the current journal other than it can
> be sealed, but I do fear he has some kind of point regarding long term
> storage.
> 
> Should there be some kind of journal archiver system that will run xz -9
> on older journals? Is this something that's being planned or is it left
> as an exercise for the reader to implement such long term
> storage/archiving systems?

systemd-journal-remote can be used (when merged) to rewrite journal
files, so the tools are mostly there.  Nevertheless, the data in
.journal files should already be compressed with XZ (if enabled), so I
doubt that that would gain much. Do you have some statistics about
the gains from the additional external XZ compression?

Zbyszek

> IMO it would be nice to be able to trigger such service when the journal
> is rotated (i.e. a templated unit) that can either just compress the
> journal in place (assuming the user does not want to be able to read
> from it actively any more) or copy a compressed version to some archive
> dir to do with as the user pleases.