On 8/13/07, Russ Allbery <[EMAIL PROTECTED]> wrote: > That -daemons value is way too high and will cause a ton of context > switches, so that isn't what you want. However, it sounded like you'd > already tried tweaking that. See the afsd man page: > > The default number of background daemons is two, enough to service > at least five simultaneous users of the machine. To increase the > number, use the -daemons argument. A value greater than six is not > generally necessary. > > That's the first thing I'd reduce if you're seeing an insane number of > context switches.
So I must have missed that chunk of the docs... I had tried dropping it down to 10 before and that didn't help the situation, I dropped it down to 6 and the performance degradation finally levels off at 8 requests per second. Context switches also dropped some, but still hover around 220,000 when I'm hitting it with 30 users. So this is at least a partial solution to my problem. > > Other than that, I looked at the original message and thought "oh, that's > interesting" but I didn't really have any useful feedback. Have you seen > jhutz's document on cache tuning? It's probably the best place to start > just to make sure that the cache values are generally reasonable and > consistent with your working set and cache size. I've looked through it before, but I usually get too annoyed when the asfd process kernel panics my machine if I get dcache/stats too high. My webservers deal with an annoying large volume of content (~35GB) and defining a working set size seems to be a moving target to say the least, but I'll take another stab at it. > Certainly, if Arla is scaling, using Arla is a valid option. I'm curious > on improving OpenAFS to match, of course, but Arla uses a considerably > different kernel architecture and I can see some theoretical reasons why > it might scale better under certain loads. Unfortunately there are other issues preventing me from using arla, and I do realize that its almost like comparing apples to oranges as far as internals go. It simply degraded how I would expect it to degrade. This is the real crux of the problem I'm running into Thank you all very much for the feedback. -- -Nathan Gordon If the database server goes down and there is no code to hear it, does it really go down? <esc>:wq<CR> _______________________________________________ OpenAFS-info mailing list [email protected] https://lists.openafs.org/mailman/listinfo/openafs-info
