Messages in this thread | | | Date | Fri, 12 Feb 1999 19:51:52 -0800 (PST) | From | Simon Kirby <> | Subject | Re: fsync on large files |
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On Fri, 12 Feb 1999, Alan Curry wrote:
> I'm coming late to this topic, but with a good reason: I just figured out > today that syslogd's fsyncs have been the cause of some major performance > problems on an ISP's central server. Load averages have been unreasonably > high and gradually getting worse. Today we realized that there is a weekly > cycle to it, and it matches the cycle of the log rotation of > /var/log/messages. As this log file grows (currently 36 megs with 2 days left > before rotation) and beyond, with syslogd fsync'ing every line it writes, > syslogd hangs for long periods of time, and when syslogd is hung, lots of > other stuff hangs. > > Previously I deleted all the messages on the large-file-fsync thread without > paying much attention, and now it seems to have died off just when I realized > I needed it. What I could find in the archive did not seem to be a conclusive > answer to what is now a pretty urgent question: would 2.2.1 do better than > 2.0.36 is doing here? And if I'm 2.2-phobic (which I'm not, but some people > are), will 2.0.37 fix this problem? > > Given that all of the stuff on this machine is pretty close to redhat 5.x > standard issue, including the syslogd and log rotation configuration, are > there lots of other people out there suffering without knowing the cause, > like I was?
There's no way in hell I'd run syslogd with fsync() enabled on a machine that longs anything more than 1 line per minute. Disable fsync()ing in syslogd by prepending "-" to each log file you want to turn it off for.
Simon-
| Simon Kirby | Systems Administration | | mailto:sim@netnation.com | NetNation Communications | | http://www.netnation.com/ | Tech: (604) 684-6892 |
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