Re: [PLUG] inotify

[Julien Vehent <julien@linuxwall.info>]

On 2012-08-15 06:01, Rich Freeman wrote:
> On Tue, Aug 14, 2012 at 11:05 PM, Julien Vehent <julien@linuxwall.info>
> wrote:
> > During the meeting tonight I mentionned inotify and how it can be used to
> > keep two directory trees in sync. I used it to keep a local directory 
> > tree,
> > that contained huge amounts of small images, in sync with a bucket in S3
> > (via s3fs).
>
> An alternative to s3fs is s3cmd.  It has a sync function which
> utilizes the fact that s3 maintains an accurate list of hashes to
> reduce file transfer.  It does still need to read the local file to
> determine the local hash. You could potentially use it in combination
> with inotify to reduce local IO, while avoiding copying files if they
> haven't actually changed.
>
> One risk of the inotify approach is that if somehow the tress do get
> out of sync they'll tend to stay that way, unless you periodically run
> a full sync.  That could happen if something is modified while it
> isn't running, or if something directly modifies the s3 tree.
>
> Rich

Yes. I used to have rsync running every X hours in parallel of inotify, for
this reason. But for the few months I had this running, I don't remember
having a single file out of sync. inotify is very stable and reliable.

- Julien
___________________________________________________________________________
Philadelphia Linux Users Group         --        http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug