Ithanks to alan_at_nabeth.cxo.dec.com for his, unfortunatly it looks
like it's just due to the way that the app uses the disk. I have
included his reply below. For those that come across this problem
and have the 'spare memory', I set up a ram disk for the app to write
to, which improved this considerably.
> User mode or kernel mode time? Also, is there a fairly
> heavy I/O load when update is running?
> If the application is writing to a UFS (instead of AdvFS)
> the file system uses two algorithms to retire dirty data
> written to the cache; if the transfer is the right size
> and alignment it schedules the write immediately and returns
> asynchronously otherwise it simply copies the data to the
> cache and lets sync worry about it. If the application is
> doing the wrong size or poorly aligned writes, then the
> buffer cache can quickly fill with dirty data. Since the
> cache is all of free memory, when a sync(2) comes around
> it can have a lot of work to do.
--
Franc Carter MEMLab, University of Sydney
Ph: 61-2-9351-7819 Fax: 9351-6461
Received on Mon Aug 16 1999 - 22:01:02 NZST