On Wednesday 16 May 2007 00:13, Paul Winkler wrote: > On Tue, May 15, 2007 at 12:00:52PM +0200, Gaute Amundsen wrote: > > I set cache-size to 10000 last night, up from the default. > > I felt I had to try that before I had a grap in place, so I don't have > > good numbers to estimate tha change, but with about 20 hits a sec on > > apache, there was close to 500000 loads the last hour, and just 3000 > > writes. > > Does that look reasonable? > > Not really. Too many loads; you're getting a lot of cache misses and > blowing out the cache a lot. Keep on doubling the cache size until > your whole working set is in RAM all the time. > Will do!
> > The built in help seems to indicate I should increase the cache until > > reads approaches zero..? > > Yeah, for some definition of "approaches". I think a more realistic > minimum would be number of threads * number of ZODB writes (since each > write potentially invalidates one cached object per thread). > That would give me 2500*6 = 15000. Looks like a reasonable goal. > It's hard to quantify the point at which you're caching enough, but > you're not even close. > I can see from the config that we tried cache-size 20000 once, but probably set it back since something else was probably the problem that time :-( > > > Also, I don't think you've mentioned what sort of app this is. > > > Is it mostly reads or are there lots of writes? > > > "Mostly reads" is a lot easier to optimize :) > > > > Big CMS system with about 70 virtual domains. > I keep mixing up the numbers here I notice, but make that ~180 hosts in apache and ~85 in zope. > Based on your activity graph, you do indeed have a lot more reads than > writes. > > What's the CMS based on? Plone? Silva? Nothing of the sort. I'ts a "innhouse" thing... Could be lots of gremlins burried there I know :-/ > Chris W. had a good point about the catalog. > > Do you have blobby data in the ZODB? (large images or files)? Those > tend to play havoc with zodb cache activity, since one OFS.Image is > stored as an arbitrarily long chain of small persistent objects. So > whereas a Plone Document or a Page Template needs only one entry in > the cache, an Image might need hundreds. > Not _that_ much. There is some from olden times, but we moved all our image stuff over into something based on phpgallery 2 years ago. thanks :) Gaute _______________________________________________ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )