[OpenAFS] Re: Openafs performance with Apache/PHP
Tue, 14 Aug 2007 11:42:33 -0500
So I loaded up ntop and isolated http, dns, ssh, afs, and mysql. I
ran the previous test (ab -k -c <users> -t 120 <url>) again for
various numbers of users and here is what I came up with:
1 user: H:29.5M D:1.8M A:4.6K M:19.9M O:1.2M
2 users: H:50.3M D:3.0M A:2.0K M:33.7M O:241.9K
3 users: H:56.1M D:3.3M A:0K M:37.8M O:234.6K
4 users: H:56.2M D:3.3M A:0K M:37.9M O:127.9K
5 users: H:48.0M D:2.9M A:2.0K M:32.4M O:246.3K
8 users: H:23.4M D:1.4M A:2.3K M:15.8M O:135.6K
10 users: H:16.6M D:1.0M A:3.8K M:11.3M O:385.6K
20 users: H:16.7M D:1.0M A:0K M:11.7M O:235.5K
30 users: H:16.8M D:1.0M A:1.9K M:11.9M O:346.2K
H - http, D - dns, A - afs, M - mysql, O - other
This shows an interesting trend in that there is a peak level of
performance, as well as a worst case performance level as well. It
also shows that afs traffic is essentially zero. This would indicate
that my performance bottleneck is in accessing the afs cache.
If I can do further diagnostics/testing let me know.
On 8/13/07, Russ Allbery <email@example.com> wrote:
> "Nate Gordon" <firstname.lastname@example.org> writes:
> > 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.
> The other thing that would be very interesting to know is whether the time
> is going into data management in the cache manager or is really going into
> network traffic to the file server. If you can use something like tcpdump
> to see how much Rx traffic there is to the file server under different
> loads and see if that increases with increasing request time or if it
> stays the same, that would be very interesting. If it stays the same,
> that points to some sort of inefficiency in the cache manager itself with
> its data structure handling.
> Russ Allbery (email@example.com) <http://www.eyrie.org/~eagle/>
If the database server goes down and there is no code to hear it, does
it really go down?