Can rsync monitor a file system?

[Christoph Biedl]

Tim H wrote...

> what about scripts running every 30 seconds on each machine,
> thats lighter then rsync just to compare..
> eg.
> 
> ---- Server1 ----
> ls -lR /* > ~/files1
> scp files1 SERVER2:~
> 
> ---- Server2 ----
> ls -lR /* > ~/files2
> (do a diff command here on files1 vs. files2)
> (if different, then run rsync -u)

Well, the things rsync does aren't much different from that. But
doing this every 30 seconds is a good way to get a lot of I/O load.

If Charles' intention is to get really fast replication he'd better
review his storage strategy. For example, using mysqld and a "slave"
daemon does this without overhead.

If there's no alternative to a file based storage, I strongly suggest to
do a triggered rsync, not polling. Linux has notifications if there was
a change in the file system (inotify, fam [file alteration monitor]).
I'm sure there are similar things for Solaris.

    Christoph