On 13.2.2012, at 21.36, Jan-Frode Myklebust wrote: >> Other things that would be interesting to try out (both from latency and >> disk IO usage point of view): >> >> - maildir_very_dirty_syncs > > We already have > > $ doveconf maildir_very_dirty_syncs > maildir_very_dirty_syncs = yes > > but I don't think this gave the advantage I was expecting.. Was > expecting this to move most iops to the index-luns, but the maildir > luns seems just as busy.
This setting should get rid of almost all readdir() calls. If it doesn't, something's not working right. >> - mail_prefetch_count (Linux+maildir only, v2.1+) > > Will look into if this works with GPFS when we upgrade to v2.1. It has > it's own page cache, so I have no idea if it will respect > POSIX_FADV_WILLNEED or if one will need to use it's own API's for > hinting: > > > http://publib.boulder.ibm.com/infocenter/clresctr/vxrx/index.jsp?topic=%2Fcom.ibm.cluster.gpfs.v3r4.gpfs300.doc%2Fbl1adm_mlacrge.html I guess if there's an easy way to lookup filename or fd -> blockNumber that wouldn't be difficult to implement with a plugin.
