Le Saturday 11 July 2009 23:34:30, Arno Lehmann a écrit : > Hello, > > 09.07.2009 16:03, Stoyan Petkov wrote: > > Hello, > > > > I've an FD that's making too much iowait on the backed up machine. I > > tried searching info on the subject but nothing useful comes up. Here is > > an excerpt from the top utility: > > > > top - 18:55:25 up 50 days, 1:48, 23 users, load average: 0.30, 0.32, > > 0.83 Tasks: 124 total, 1 running, 123 sleeping, 0 stopped, 0 zombie > > Cpu0 : 2.0%us, 1.0%sy, 0.0%ni, 96.0%id, 0.0%wa, 1.0%hi, 0.0%si, > > 0.0%st > > Cpu1 : 2.9%us, 1.0%sy, 0.0%ni, 96.1%id, 0.0%wa, 0.0%hi, 0.0%si, > > 0.0%st > > Unless I'm mistaken, there's not much iowait displayed here. Quite the > contrary: 96% idle. > > > Mem: 1032680k total, 1016456k used, 16224k free, 18468k buffers > > Swap: 2031608k total, 103044k used, 1928564k free, 645912k cached > > > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > > 22534 root 20 0 41560 2268 1232 S 6.0 0.2 0:06.32 bacula-fd > > -c /etc/bacula/bacula-fd.conf > > 22758 root 20 0 2364 1044 812 R 1.0 0.1 0:01.40 top > > > > > > During normal operation the iowait will stay within 10% limits, however, > > at some point it jumps to 90-98% and stays that way. I've noticed that > > even with canceling the job from the director, > > Have you tried vmstat, and checked - perhaps using ps - which > processes do need lots of CPU time when there's so much iowait occuring?
I don't see why having iowait should be a bad thing for a backup application : iowait is the time the CPU spends waiting for IO (disks...), which should be most of the time while doing a backup (except if compressing, encrypting, or a very badly programmed backup application). There are several reasons why the iowait could raise : - More IO to be done for a portion of the backup (small files for instance) for the same volume of data to be sent through the network - Another application used the CPU during the first part of the backup while bacula was waiting for IO and has stopped using it (you should go from 100%CPU to high iowait). But still I don't see a problem with the FD putting a CPU at 100% IOWait, that should be normal behaviour. Anyway, if you really want to investigate this, you could do a strace on FD at the moment it is at 100% IOWait, then we'll know what it's waiting for :) ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
