>> About 30% of all I/O is to mailboxes.db, most of which is read. I > Solaris 10 does this in my case. Via dtrace you'll see that open() on the > mailboxes.db and read-calls do not exceed microsecond ranges. mailboxes.db > is not the problem here. It is entirely cached and rarely written > (creating, deleting and moving a mailbox). So what does "30% of all I/O" mean in that original statement? Does that mean "30% of all IO requests from application to OS" or does that mean "30% of all IO requests from OS to IO device"? I assumed you meant the second because usually accessing data cached in memory isn't actually considered IO by most people... Rob ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html