Server seems slow - where to start?

Hi jvieille, when you say its slow can you give more details ?
Is one particular page or section of the site slow ?
Is the whole site slow ?
Was the performance ok once and its just gone slow or has something happened ?
Has the traffic increase ?

You might want to look at putting something like Munin (http://munin-monitoring.org/) on your server which will measure there performance of the servers and the apps so you can get a better picture of what is happening, ab's just give a one of snap shot in time ?

What version of mysql you running ? which database engine are you running ? if mysql is your problem you might want to look at 5.5 much better suited fore multi cores and just performances a whole lot better than 5.1

Cheers Nick

There doesn't seem to be any caching on the first site. It could definitely benefit enormously from caching for anonymous users. The site is taking around 1.5 seconds to load the front page, and most other pages I tried to visit.

You can use devel to get a list of the queries on a page load, and the time they take. You can also setup xhprof and profile the page to see where time is being spent.

I don't see either a reason why either of the servers would be slow based on munin.

Something to do with my Drupal installs definitely!
I ran AB on 2 different sites on the same server
- the first on an empty Drupal site, in maintenance mode - the least we can do with a Drupal site...
- the second on a non Drupal, pure html site

Below the results of the test:

Server (1) - Empty Drupal in maintenance mode

root@ks311625:~# ab -c50 -n500 http://www.8895b2mml.net/
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking www.8895b2mml.net (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Finished 500 requests

Server Software: Apache/2.2.9
Server Hostname: www.8895b2mml.net
Server Port: 80

Document Path: /
Document Length: 4625 bytes

Concurrency Level: 50
Time taken for tests: 135.913 seconds
Complete requests: 500
Failed requests: 0
Write errors: 0
Non-2xx responses: 500
Total transferred: 2650500 bytes
HTML transferred: 2312500 bytes
Requests per second: 3.68 [#/sec] (mean)
Time per request: 13591.264 [ms] (mean)
Time per request: 271.825 [ms] (mean, across all concurrent requests)
Transfer rate: 19.04 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.6 0 9
Processing: 8419 13435 987.3 13576 17058
Waiting: 8419 13434 987.2 13576 17058
Total: 8420 13435 987.3 13576 17059

Percentage of the requests served within a certain time (ms)
50% 13576
66% 13868
75% 14010
80% 14116
90% 14406
95% 14581
98% 15057
99% 15669
100% 17059 (longest request)

Server (2) - Dreamweaver site

root@ks311625:~# ab -c50 -n500 http://www.isa-france.org/
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking www.isa-france.org (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Finished 500 requests

Server Software: Apache/2.2.9
Server Hostname: www.isa-france.org
Server Port: 80

Document Path: /
Document Length: 780 bytes

Concurrency Level: 50
Time taken for tests: 0.105 seconds
Complete requests: 500
Failed requests: 0
Write errors: 0
Total transferred: 591000 bytes
HTML transferred: 390000 bytes
Requests per second: 4777.79 [#/sec] (mean)
Time per request: 10.465 [ms] (mean)
Time per request: 0.209 [ms] (mean, across all concurrent requests)
Transfer rate: 5514.98 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.2 0 1
Processing: 2 10 1.6 10 12
Waiting: 2 10 1.6 10 12
Total: 3 10 1.5 10 13

Percentage of the requests served within a certain time (ms)
50% 10
66% 10
75% 11
80% 11
90% 11
95% 12
98% 12
99% 12
100% 13 (longest request)

I'd personally also add memcache to the mix for when pages need to be re-generated and are out of the boost cache. Adding varnish, too is also an option.

But I think you have some process in there that is delaying the page load as I can't see page waiting times of 1.5s on any installation even with many many modules installed (normally number one problem for slowness on drupal).

So: Check your modules.

Easiest is to use xdebug and see what function is taking so long ...

Thanks and Best Wishes,

Fabian