Mike -- EMAIL IGNORED wrote:
On Tue, 04 Aug 2009 21:31:22 +0200, Kai Schaetzl wrote:
Mike -- EMAIL IGNORED wrote on Tue, 4 Aug 2009 16:56:22 +0000 (UTC):
Please refer to my thread "excessive DNS slows httpd"
Why don't you keep posting in there then?
Because the new title reflects a new focus, and I hoped to attract different people.
Suggestions would be most welcome.
Foremost, you want to find out why those queries are generated despite the fact that hostnamelookups are off. That is surely something in your configuration or a web application. It's not a general problem of Apache on CentOS, mine are all not doing that.
Kai
Until now, for a long time, mine wasn't doing it either.
Part of the problem was suggested by someone on the Apache group; there are two problems:
Both boxes have nscd, but it was not running on the CentOS box. Now that I fixed that, all but the first connection are rapid, as you might expect.
We still do not why the change in httpd.conf caused the problem to appear. However, my belief that there was a difference between the two machines is accounted for by the difference in /etc/init.d/nscd . When I tried it for the first time this morning, the box that previously been fast was slow. No doubt, the nscd storage had timed out.
Except that nscd was not set to run, it is probably not specifically a CentOS problem. Perhaps I made a wrong choice in setup?
If I really want to know what is different between two boxes, I'll do something like NFS mount one into the other or rsync their /etc trees somewhere on a common host and let diff -r walk through them.
Are you sure this isn't as simple as having (and using, check your resolv.conf) a caching name server running on one box so most lookups are resolved locally while the other is making the query to something slow?