dovecot - Apr 2011 - inotify and network/cluster filesystems

(dovecot v1.2.16)

I've notice the log notices about increasing
/proc/sys/fs/inotify/max_user_instances on my servers, and started
wondering if inotify works for network/cluster filesystems..

I found this:

	http://www.ibm.com/developerworks/forums/thread.jspa?threadID=311194

which says that there's no mechanism for one node to tell another node
that a directory changed for GPFS.. And I would assume the same applies for
NFS and other network filesystems. (Yes I know, we should use director
to make users sticky to one host -- but we're not yet ready for that for
lmtp).

So, are there any recommendations for what settings one should use for
for filesystems where inotify woun't work ? Are there settings for
disabling it (without recompiling)? 

And does mailbox_idle_check_interval happen in addition to inotify, so
that clients will be notified even with a broken inotify ?


  -jf

On 1.4.2011, at 10.52, Jan-Frode Myklebust wrote:
> I've notice the log notices about increasing
> /proc/sys/fs/inotify/max_user_instances on my servers, and started
> wondering if inotify works for network/cluster filesystems..
> 
> I found this:
> 
> 	http://www.ibm.com/developerworks/forums/thread.jspa?threadID=311194
> 
> which says that there's no mechanism for one node to tell another node
> that a directory changed for GPFS.. And I would assume the same applies for
> NFS and other network filesystems. (Yes I know, we should use director
> to make users sticky to one host -- but we're not yet ready for that
for
> lmtp).
Right. But it should still work if the modifications come from the same system.
So it's better than nothing.
> So, are there any recommendations for what settings one should use for
> for filesystems where inotify woun't work ? Are there settings for
> disabling it (without recompiling)? 
Why not just keep it enabled? There shouldn't be any down side to it.
> And does mailbox_idle_check_interval happen in addition to inotify, so
> that clients will be notified even with a broken inotify ?
Yes.