On Fri, Dec 07, 2007 at 12:38:11 +0000, Darren J Moffat wrote: : Dickon Hood wrote: : >We've got an interesting application which involves recieving lots of : >multicast groups, and writing the data to disc as a cache. We're : >currently using ZFS for this cache, as we're potentially dealing with a : >couple of TB at a time.
: >The threads writing to the filesystem have real-time SCHED_FIFO priorities : >set to 25. The processes recovering data from the cache and moving it : >elsewhere are niced at +10. : >We're seeing the writes stall in favour of the reads. For normal : >workloads I can understand the reasons, but I was under the impression : >that real-time processes essentially trump all others, and I'm surprised : >by this behaviour; I had a dozen or so RT-processes sat waiting for disc : >for about 20s. : Are the files opened with O_DSYNC or does the application call fsync ? No. O_WRONLY|O_CREAT|O_LARGEFILE|O_APPEND. Would that help? -- Dickon Hood Due to digital rights management, my .sig is temporarily unavailable. Normal service will be resumed as soon as possible. We apologise for the inconvenience in the meantime. No virus was found in this outgoing message as I didn't bother looking. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
