Re: fsync on large files

Oliver Xymoron (oxymoron@waste.org)
Sat, 13 Feb 1999 00:06:42 -0600 (CST)


On Sat, 13 Feb 1999, Alan Curry wrote:

> Simon Kirby writes the following:
> >
> >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.
>
> I know that, and I've already done that as a temporary solution. But syslogd
> syncs every line written for a good reason, namely that if the machine
> crashes you don't want to lose the last few lines that were logged. They are
> the most likely place to look for suspicious happenings. So I want a proper
> fix, not a "disable the safety feature" kludge.

There's a fair chance you'll lose the lines you're really interested in if
you crash anyway - as you've noticed, syncing is a sometimes an intensive
operation. A _real_ fix, which also deals with log security issues nicely,
is to log across a serial port to a secure (possibly non-networked) host.

--
 "Love the dolphins," she advised him. "Write by W.A.S.T.E.." 

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