On Wed, Feb 17, 2016 at 12:49 AM, Alessio Cecchi <[email protected]> wrote:
> Hi, I'm are running a classic Dovecot setup: > > About ten thousand connected users > mailbox in Maildir format shared via NFS (NetApp) > Director for POP/IMAP > Delivery via Dovecot LDA > > All works fine but sometimes I see a spike on the load of POP/IMAP servers > and high disk usage (close to 100%) on NFS NetApp. > > When this happens on NFS stats (of POP/IMAP) I can see an high volume of > "lookup, remove, rename" requests. > > Example (avg is during normal load, max is request number during the > spike): > > Lookup avg 100 max 700 > Remove avg 50 max 300 > Rename avg 50 max 300 > Getattr avg 200 max 250 > Total NFS avg 600 max 1800 > > I think that some users are doing some kinds of "intensive" operations on > their mailbox but what and who? > > I am currently using "iotop" to monitor the activity of individual users > but I can't figure out who is causing the high number of I/O requests. > > > One suggestions is that I'd walk those directories and see if someone has a mailbox with 100k files in it.
