AW: [DRBD-user] Re: file replication between sites

[Martin Bene]

Hi Dan,

> You could probably also run multiple instances of csync2 on a 
> server in order to speed up replication if data can be 
> properly segregated.  You will of course have the lag between 
> the time someone opens up a DWG file and the time the lock 
> files get to the other server.

I don't think this is the best approach - why not use the csync2 hint
facility with inotify?

I'm using csync2 to keep two fileservers with ~500.000 files totaling
400GB in sync; normal sync is rather slow for this setup, scanning these
500.000 files for changes _does_ take some time.

However: on a linux box with inotify support compiled into the kernel
you can feed csync2 with filesystem notification events and then have
csync2 just check & sync these files/directories instead of scanning the
whole fileserver.

You can use something like 

/usr/bin/inotifywait --format '%w%f' -qmr -e CLOSE_WRITE \
	-e CREATE -e DELETE -e MOVE -e ATTRIB /data/ 2>&1 | \
	xargs -L 1 /usr/sbin/csync2 -h 2>/dev/null &

to feed the csync2 hints table and then run 

	csync2 -cu 

Every minute or so. Works quite well for me. For even faster syncs, you
could try adding the actual sync to the action triggered by inotify -
haven't played with that yet, 1 sync/minute is good enough for me.

Bye, Martin