Buffer flushing

[Michael Meissner]

In article <911 at sixhub.UUCP> davidsen at sixhub.UUCP (Wm E. Davidsen Jr)
writes:

|   Most flavors of SysV and some BSD systems have a process which does a
| sync from time to time, such as "update." When the kernel is configured
| to have a large number of buffers the result is a slowdown in
| performance for disk intensive tasks.
| 
|   Many versions provide a tuning parameter which allows this to happen
| more or less often, but it still happens all at once. What I would like
| is a way to force or at least encourage the system to write dirty
| buffers out as a idle task, so that if the CPU is available and there
| are dirty buffers they are queued, but only at some faitly slow rate,
| perhaps 3-5% of the buffers per second.

The only problem with doing this only as an idle task, is that you
risk losing lots of data if you have a crash when the system hasn't
been idle for awhile (remember murphy after all).  You could of course
have a general sync, say every 5 minutes or so in addition to doing it
on idle cycles.
--
Michael Meissner	email: meissner at osf.org		phone: 617-621-8861
Open Software Foundation, 11 Cambridge Center, Cambridge, MA

Catproof is an oxymoron, Childproof is nearly so