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Troubleshooting intermittent performance issues for LAMP server

Posted on 2008-10-22
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Last Modified: 2013-12-13
We have an e-learning application developed in PHP/MySQL running on a Linux VPS with Apache.  We are having issues where at some times of the day pages are being served very slowly, not just PHP pages but also static images, JS files, etc.  Normally it's slowest when there are more users on the site, which is normally between 3-6pm, other time of the day it seems to be very fast.

We are aware of some particularly problematic pages which run slowly and execute multiple SQL queries.  However I'm not convinced that this is the reason for the slowdown of the server.

I've been looking at this problem on and off over the last few weeks and my gut feeling is that it's not necessarily a problem directly with PHP or MySQL but something to do with Apache serving the requests and running out of threads.  The server isn't particularly busy, it sits normally at 0% CPU and has 400MB RAM free.  I just don't have enough expertise to be able to pin-point the exact problem and don't know what at the best tools to help me.

I would like to confirm that the server config is optimal and hopefully work out where the bottle neck is (i.e. is it a particular PHP page or MySQL query, or a problem with the Apache config) so that we can improve the performance and also know what to do better the next time!

I'm not sure what details are required to troubleshoot this, I'm including a netstat, top and mysql slow log output.  What else is needed?

Final remark, I added the %T flag to Apache's LogFormat to be able to see the time taken for each request.  While some requests are taking longer, ones which I know took a long time to load are still showing zero seconds, making me thing that the problem is that the requests might be getting queued up before Apache received them or acknowledged them.

Any help / suggestions / pointers in the right direction are much appreciated.

Andy

Output from "top" during a particulary slow period:
---------------------------------------------------
 
top - 18:06:54 up 17:28,  3 users,  load average: 0.43, 0.33, 0.18
Tasks:  54 total,   1 running,  53 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0% us,  0.0% sy,  0.0% ni, 99.8% id,  0.1% wa,  0.0% hi,  0.0% si
Mem:    524288k total,   126260k used,   398028k free,        0k buffers
Swap:        0k total,        0k used,        0k free,        0k cached
 
  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
19887 root      16   0  2092 1104  856 R    0  0.2   0:00.20 top
    1 root      16   0  1800  668  564 S    0  0.1   0:00.08 init
17832 root      16   0  1496  576  456 S    0  0.1   0:00.57 syslogd
17902 root      19   0  2544 1340 1068 S    0  0.3   0:00.01 mysqld_safe
18010 mysql     16   0  134m  23m 5728 S    0  4.6  55:47.32 mysqld
18011 root      15   0  1424  496  432 S    0  0.1   0:00.00 logger
18209 root      18   0  3992  840  640 S    0  0.2   0:00.00 couriertcpd
18212 root      18   0  2908  736  564 S    0  0.1   0:00.00 courierlogger
18242 root      18   0  3992  840  640 S    0  0.2   0:00.00 couriertcpd
18245 root      18   0  2908  736  564 S    0  0.1   0:00.00 courierlogger
18255 root      21   0  3992  840  640 S    0  0.2   0:00.00 couriertcpd
18257 root      18   0  2908  736  564 S    0  0.1   0:00.00 courierlogger
18266 root      21   0  3992  840  640 S    0  0.2   0:00.00 couriertcpd
18269 root      18   0  2908  736  564 S    0  0.1   0:00.00 courierlogger
18309 root      15   0  2112  832  664 S    0  0.2   0:00.08 xinetd
18418 bind      19   0 36276 2968 1888 S    0  0.6   0:00.09 named
19512 qmails    17   0  1484  400  312 S    0  0.1   0:00.03 qmail-send
19515 qmaill    15   0  1436  456  392 S    0  0.1   0:00.00 splogger
19516 root      18   0  1464  360  272 S    0  0.1   0:00.00 qmail-lspawn
19517 qmailr    18   0  1460  356  268 S    0  0.1   0:00.00 qmail-rspawn
19518 qmailq    18   0  1432  336  276 S    0  0.1   0:00.00 qmail-clean
19780 root      16   0 30788  12m 7764 S    0  2.5   0:01.58 apache2
19960 root      16   0 36996 5476 3500 S    0  1.0   0:00.02 httpsd
19963 psaadm    15   0 44008  28m  19m S    0  5.5   0:01.62 httpsd
20096 root      16   0  4772 1084  748 S    0  0.2   0:01.21 sshd
20382 root      15   0  2040  852  676 S    0  0.2   0:00.07 cron
27796 root      17   0  8896 2536 1984 S    0  0.5   0:00.16 sshd
27939 netlangu  15   0  9064 1816 1240 S    0  0.3   0:02.29 sshd
13966 psaadm    16   0 45856  30m  19m S    0  5.9   0:01.38 httpsd
14048 psaadm    15   0 43516  26m  17m S    0  5.1   0:01.59 httpsd
 7236 root      16   0  8896 2532 1980 S    0  0.5   0:00.13 sshd
 7556 netlangu  16   0  9060 1816 1232 S    0  0.3   0:01.00 sshd
 7567 netlangu  15   0  3176 1912 1248 S    0  0.4   0:00.09 bash
 7964 root      16   0  8896 2532 1980 S    0  0.5   0:00.05 sshd
 8026 netlangu  16   0  8900 1788 1228 S    0  0.3   0:00.21 sshd
 8029 netlangu  15   0  3224 1956 1244 S    0  0.4   0:00.06 bash
20010 www-data  16   0 35040  14m 5372 S    0  2.8   0:03.48 apache2
 9869 www-data  15   0 31280 9988 4228 S    0  1.9   0:00.75 apache2
14091 www-data  16   0 35068  14m 5420 S    0  2.9   0:00.69 apache2
27664 root      16   0  5040 1528 1136 S    0  0.3   0:00.00 su
27737 root      16   0  2668 1652 1244 S    0  0.3   0:00.01 bash
 9667 www-data  16   0 35056  14m 5348 S    0  2.8   0:00.81 apache2
 9684 www-data  16   0 36664  15m 4664 S    0  3.0   0:00.69 apache2
15741 www-data  16   0 31348  10m 4992 S    0  2.1   0:00.63 apache2
15746 www-data  16   0 34968  13m 4512 S    0  2.7   0:00.51 apache2
15747 www-data  16   0 31220  10m 5040 S    0  2.1   0:00.67 apache2
20285 www-data  16   0 35056  13m 4580 S    0  2.7   0:00.69 apache2
21864 www-data  16   0 31204  10m 4964 S    0  2.0   0:00.47 apache2
 
 
Output from "netstat" during a slow period:
-------------------------------------------
root@netlanguages:/var/www/vhosts/netlanguages.com# netstat -t -n
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp      705      0 79.170.194.137:80       84.127.74.175:48754     ESTABLISHED
tcp        0      0 79.170.194.137:80       90.163.59.214:49338     ESTABLISHED
tcp        0      0 79.170.194.137:80       90.163.59.214:49336     ESTABLISHED
tcp        0      0 79.170.194.137:80       90.163.59.214:49334     ESTABLISHED
tcp        0      0 79.170.194.137:80       90.163.59.214:49332     FIN_WAIT2
tcp        0      1 79.170.194.137:80       85.58.10.19:3592        LAST_ACK
tcp        0      0 79.170.194.137:80       62.57.44.213:4887       ESTABLISHED
tcp        0      0 79.170.194.137:80       62.57.44.213:4886       ESTABLISHED
tcp        0      0 79.170.194.137:80       62.57.44.213:4888       ESTABLISHED
tcp        0      0 79.170.194.126:22       80.33.133.83:3494       ESTABLISHED
tcp        0      0 79.170.194.137:80       83.34.133.42:17604      TIME_WAIT
tcp      684      0 79.170.194.137:80       80.174.164.61:63348     ESTABLISHED
tcp        0      0 79.170.194.137:80       80.174.164.61:63347     TIME_WAIT
tcp      557      0 79.170.194.137:80       85.58.36.65:61210       ESTABLISHED
tcp      444      0 79.170.194.137:80       88.22.67.218:1845       ESTABLISHED
tcp        0      0 79.170.194.126:22       80.33.133.83:3728       ESTABLISHED
tcp        0      1 79.170.194.137:80       77.208.139.120:1449     FIN_WAIT1
tcp      552      0 79.170.194.137:80       77.208.139.120:1450     ESTABLISHED
tcp        0   3033 79.170.194.137:80       212.59.221.14:50281     FIN_WAIT1
tcp        0   2248 79.170.194.126:22       80.33.133.83:3397       ESTABLISHED
tcp        0      0 79.170.194.126:22       80.33.133.83:2592       ESTABLISHED
tcp      797      0 79.170.194.137:80       84.88.36.27:28340       ESTABLISHED
tcp        0      0 79.170.194.137:80       77.224.48.105:1364      ESTABLISHED
tcp        0      0 79.170.194.137:80       77.224.48.105:1370      TIME_WAIT
tcp        0      0 79.170.194.137:80       77.224.48.105:1368      ESTABLISHED
tcp      536      0 79.170.194.137:80       77.224.48.105:1374      ESTABLISHED
tcp        0      0 79.170.194.137:80       77.224.48.105:1372      ESTABLISHED
tcp        0   2577 79.170.194.137:80       88.15.147.165:29644     LAST_ACK
tcp        0   2577 79.170.194.137:80       88.15.147.165:29645     LAST_ACK
tcp        0   2588 79.170.194.137:80       88.15.147.165:29646     LAST_ACK
tcp        0   2577 79.170.194.137:80       88.15.147.165:29647     LAST_ACK
tcp        0   5143 79.170.194.137:80       88.15.147.165:29640     LAST_ACK
tcp        0   5143 79.170.194.137:80       88.15.147.165:29641     LAST_ACK
tcp        0   2577 79.170.194.137:80       88.15.147.165:29642     LAST_ACK
tcp        0   2577 79.170.194.137:80       88.15.147.165:29643     LAST_ACK
tcp        0      0 79.170.194.137:80       83.35.158.152:1776      FIN_WAIT2
tcp        0      0 79.170.194.137:80       88.18.60.176:10041      FIN_WAIT2
tcp      121      0 79.170.194.137:80       213.27.221.227:2178     CLOSE_WAIT
tcp      607      0 79.170.194.137:80       87.217.138.252:1310     ESTABLISHED
tcp        0      0 79.170.194.137:80       81.34.86.92:2225        FIN_WAIT2
tcp        0      0 79.170.194.137:80       81.34.86.92:2197        TIME_WAIT
tcp      529      0 79.170.194.137:80       80.33.133.83:3420       ESTABLISHED
tcp      451      0 79.170.194.137:80       80.174.133.95:1958      ESTABLISHED
tcp        0      0 79.170.194.137:80       80.174.133.95:1955      FIN_WAIT2
tcp        0      0 79.170.194.137:80       80.174.133.95:1953      TIME_WAIT
tcp        0      0 79.170.194.137:80       87.219.67.151:1073      TIME_WAIT
tcp      554      0 79.170.194.137:80       87.219.67.151:1076      ESTABLISHED
tcp      571      0 79.170.194.137:80       81.34.86.92:2265        ESTABLISHED
tcp      822      0 79.170.194.137:80       193.130.97.35:25637     ESTABLISHED
 
 
A sample of some queries from MySQL slow log:
---------------------------------------------
# Time: 081022 16:47:07
# User@Host: discovia[discovia] @ localhost []
# Query_time: 11  Lock_time: 0  Rows_sent: 39  Rows_examined: 374
SELECT id, name FROM student_groups WHERE student_groups.id IN
        (SELECT users.student_group FROM users
        INNER JOIN user_assigned_units ON users.id = user_assigned_units.user_id
        WHERE user_assigned_units.tutor_id = 321) ORDER BY name;
# Time: 081022 17:00:44
# User@Host: discovia[discovia] @ localhost []
# Query_time: 12  Lock_time: 0  Rows_sent: 39  Rows_examined: 374
SELECT id, name FROM student_groups WHERE student_groups.id IN
        (SELECT users.student_group FROM users
        INNER JOIN user_assigned_units ON users.id = user_assigned_units.user_id
        WHERE user_assigned_units.tutor_id = 321) ORDER BY name;
# Time: 081022 17:03:05
# User@Host: discovia[discovia] @ localhost []
# Query_time: 11  Lock_time: 0  Rows_sent: 37  Rows_examined: 374
SELECT id, name FROM student_groups WHERE student_groups.id IN
        (SELECT users.student_group FROM users
        INNER JOIN user_assigned_units ON users.id = user_assigned_units.user_id
        WHERE user_assigned_units.tutor_id = 327) ORDER BY name;
# Time: 081022 17:13:38
# User@Host: discovia[discovia] @ localhost []
# Query_time: 11  Lock_time: 0  Rows_sent: 39  Rows_examined: 374
SELECT id, name FROM student_groups WHERE student_groups.id IN
        (SELECT users.student_group FROM users
        INNER JOIN user_assigned_units ON users.id = user_assigned_units.user_id
        WHERE user_assigned_units.tutor_id = 321) ORDER BY name;
# Time: 081022 17:14:02
# User@Host: discovia[discovia] @ localhost []
# Query_time: 11  Lock_time: 0  Rows_sent: 39  Rows_examined: 374
SELECT id, name FROM student_groups WHERE student_groups.id IN
        (SELECT users.student_group FROM users
        INNER JOIN user_assigned_units ON users.id = user_assigned_units.user_id
        WHERE user_assigned_units.tutor_id = 321) ORDER BY name;
# Time: 081022 17:14:36
# User@Host: discovia[discovia] @ localhost []
# Query_time: 11  Lock_time: 0  Rows_sent: 51  Rows_examined: 374
SELECT id, name FROM student_groups WHERE student_groups.id IN
        (SELECT users.student_group FROM users
        INNER JOIN user_assigned_units ON users.id = user_assigned_units.user_id
        WHERE user_assigned_units.tutor_id = 322) ORDER BY name;
# Time: 081022 17:14:55
# User@Host: discovia[discovia] @ localhost []
# Query_time: 11  Lock_time: 0  Rows_sent: 51  Rows_examined: 374
SELECT id, name FROM student_groups WHERE student_groups.id IN
        (SELECT users.student_group FROM users
        INNER JOIN user_assigned_units ON users.id = user_assigned_units.user_id
        WHERE user_assigned_units.tutor_id = 322) ORDER BY name;
# Time: 081022 17:43:51
# User@Host: discovia[discovia] @ localhost []
# Query_time: 11  Lock_time: 0  Rows_sent: 51  Rows_examined: 375
SELECT id, name FROM student_groups WHERE student_groups.id IN
        (SELECT users.student_group FROM users
        INNER JOIN user_assigned_units ON users.id = user_assigned_units.user_id
        WHERE user_assigned_units.tutor_id = 322) ORDER BY name;

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Question by:andycas
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Expert Comment

by:Xyptilon2
ID: 22783235
First of all, add a swap file, so in busy moment, your box doesnt run out of memory, you can do this with:

cd /
dd if=/dev/zero of=/swap1 bs=1024 count=1048576            # Make a 1GB file
mkswap /swap1 1048576                              # Make file swap device
sync; sync                                    # Flush file system buffers
swapon /swap1                                    # Activate swap page

Second, you can enable the status logger in Apache. The relevant portion is probably commented out in your apache config, but it looks something like

# Allow server status reports, with the URL of http://servername/server-status
# Change the ".your_domain.com" to match your domain to enable.
#
#<Location /server-status>
#    SetHandler server-status
#    Order deny,allow
#    Deny from all
#    Allow from .your_domain.com
#</Location>

You can then go to http://www.yourdomain.com/server-status and see some useful "per request" information.

Third...do you have any information in your apache error_log ? For example that there are too few available servers?
0
 

Author Comment

by:andycas
ID: 22788075
@Xyptilon2:

Many thanks for the reply and suggestions.

1. The server doesn't want to let me turn on swap - maybe because it's a virtual server:
root@netlanguages:/# swapon /swap1
swapon: /swap1: Operation not permitted

It has burst memory available, it has 512MB normally but automatically has access to more if necessary.  As it sits at 400MB free (according to "top") even when it's running slowly I don't think it's a memory problem.

2. I've attached the output from server-status below, again at a point when it's running slowly.  The server-status page itself took about 30 seconds to display!  Is "0 idle workers" a sign that I need to increase something in my apache settings?

3. I'll check the error_log shortly and post what I find in it here.

Thanks,

Andy

Server Version: Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8
Server Built: Aug 16 2007 22:41:15
 
Current Time: Thursday, 23-Oct-2008 18:37:30 CEST
Restart Time: Thursday, 23-Oct-2008 15:55:54 CEST
Parent Server Generation: 2
Server uptime: 2 hours 41 minutes 35 seconds
10 requests currently being processed, 0 idle workers
 
RRKRRKRWKK......................................................
................................................................
................................................................
................................................................
 
Scoreboard Key:
"_" Waiting for Connection, "S" Starting up, "R" Reading Request,
"W" Sending Reply, "K" Keepalive (read), "D" DNS Lookup,
"C" Closing connection, "L" Logging, "G" Gracefully finishing,
"I" Idle cleanup of worker, "." Open slot with no current process
 
PID Key:
 
   17642 in state: R ,   3268 in state: R ,   17907 in state: K 
   3342 in state: R ,   32685 in state: R ,   32739 in state: K 
   17668 in state: R ,   3453 in state: W ,   3461 in state: K 
   22259 in state: K ,

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Expert Comment

by:Xyptilon2
ID: 22788681
Perhaps yes, what are the settings for your StartServers, SpareServers? They are in your apache2.conf or httpd.conf file.
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Author Comment

by:andycas
ID: 22790342
Okay, I've run apache -V and it looks like apache is in prefork mode (which seems to be what it should be from what I've read).  It says:
    Server compiled with....
     -D APACHE_MPM_DIR="server/mpm/prefork"
That means it's prefork mode, right?

Below are the relevant (I think) bits of what's in my apache2.conf.

<IfModule prefork.c>
StartServers       1
MinSpareServers    1
MaxSpareServers    5
MaxClients        10
MaxRequestsPerChild  0
</IfModule>

According to the comments in the file MaxClients is the "maximum number of server processes allowed to start" but according to the docs it seems to be the number of simultaneous requests to the server.  And 10 seems to be incredibly low!

FYI, these are the Apache settings as the server was provided to us by the VPS hosting provider.  I've just looked at a different VPS from a different provider and that one has very different values (like MaxClients of 256).  What would you recommend that I change them to?

Thanks.
Relevant bits from apache2.conf file:
-------------------------------------
 
# Timeout: The number of seconds before receives and sends time out.
Timeout 300
 
# KeepAlive: Whether or not to allow persistent connections (more than
# one request per connection). Set to "Off" to deactivate.
KeepAlive On
 
# MaxKeepAliveRequests: The maximum number of requests to allow
# during a persistent connection. Set to 0 to allow an unlimited amount.
# We recommend you leave this number high, for maximum performance.
MaxKeepAliveRequests 100
 
# KeepAliveTimeout: Number of seconds to wait for the next request from the
# same client on the same connection.
KeepAliveTimeout 15
 
##
## Server-Pool Size Regulation (MPM specific)
##
 
# prefork MPM
# StartServers ......... number of server processes to start
# MinSpareServers ...... minimum number of server processes which are kept spare
# MaxSpareServers ...... maximum number of server processes which are kept spare
# MaxClients ........... maximum number of server processes allowed to start
# MaxRequestsPerChild .. maximum number of requests a server process serves
<IfModule prefork.c>
StartServers       1
MinSpareServers    1
MaxSpareServers    5
MaxClients        10
MaxRequestsPerChild  0
</IfModule>
 
# pthread MPM
# StartServers ......... initial  number of server processes to start
# MaxClients ........... maximum  number of server processes allowed to start
# MinSpareThreads ...... minimum  number of worker threads which are kept spare
# MaxSpareThreads ...... maximum  number of worker threads which are kept spare
# ThreadsPerChild ...... constant number of worker threads in each server process
# MaxRequestsPerChild .. maximum  number of requests a server process serves
<IfModule worker.c>
StartServers       1
MaxClients        10
MinSpareThreads    1
MaxSpareThreads    4
ThreadsPerChild     25
MaxRequestsPerChild  0
</IfModule>
 
# perchild MPM
# NumServers ........... constant number of server processes
# StartThreads ......... initial  number of worker threads in each server process
# MinSpareThreads ...... minimum  number of worker threads which are kept spare
# MaxSpareThreads ...... maximum  number of worker threads which are kept spare
# MaxThreadsPerChild ... maximum  number of worker threads in each server process
# MaxRequestsPerChild .. maximum  number of connections per server process (then it dies)
<IfModule perchild.c>
NumServers           5
StartThreads         5
MinSpareThreads    1
MaxSpareThreads    4
MaxThreadsPerChild  20
MaxRequestsPerChild  0
AcceptMutex fcntl
</IfModule>

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by:andycas
ID: 22791315
Just wanted to add the response to your original third question, that the error_log doesn't seem to have too many warnings, which surprises me a bit. I've included it for all of October with unrelated errors removed (file not founds, etc).

The only errors of note I see are four of these:
    [error] server reached MaxClients setting, consider raising the MaxClients setting
What's interesting is that there have been many times when the server has been running very slowly but none of these MaxClients errors have appears.  Is that normal?
[Tue Oct 07 10:30:53 2008] [notice] Graceful restart requested, doing restart
[Tue Oct 07 10:30:54 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Tue Oct 07 10:30:55 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Tue Oct 07 12:10:08 2008] [notice] Graceful restart requested, doing restart
[Tue Oct 07 12:10:09 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Tue Oct 07 12:10:09 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Tue Oct 07 12:11:02 2008] [notice] Graceful restart requested, doing restart
[Tue Oct 07 12:11:02 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Tue Oct 07 12:11:03 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Tue Oct 07 19:06:49 2008] [notice] caught SIGTERM, shutting down
[Tue Oct 07 19:08:38 2008] [warn] Init: Session Cache is not configured [hint: SSLSessionCache]
[Tue Oct 07 19:08:38 2008] [notice] suEXEC mechanism enabled (wrapper: /usr/lib/apache2/suexec2)
[Tue Oct 07 19:08:38 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Tue Oct 07 19:08:40 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Tue Oct 07 19:08:47 2008] [error] server reached MaxClients setting, consider raising the MaxClients setting
[Mon Oct 13 18:33:47 2008] [notice] caught SIGTERM, shutting down
[Mon Oct 13 18:35:53 2008] [warn] Init: Session Cache is not configured [hint: SSLSessionCache]
[Mon Oct 13 18:35:53 2008] [notice] suEXEC mechanism enabled (wrapper: /usr/lib/apache2/suexec2)
[Mon Oct 13 18:35:53 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Mon Oct 13 18:35:57 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Mon Oct 13 18:36:02 2008] [error] server reached MaxClients setting, consider raising the MaxClients setting
[Mon Oct 13 18:41:39 2008] [notice] SIGHUP received.  Attempting to restart
[Mon Oct 13 18:41:39 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Mon Oct 13 18:41:40 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Wed Oct 15 17:57:44 2008] [notice] SIGHUP received.  Attempting to restart
[Wed Oct 15 17:57:44 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Wed Oct 15 17:57:45 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 16 16:41:25 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 16 16:41:25 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 16 16:41:26 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 16 16:56:32 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 16 16:56:32 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 16 16:56:32 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 16 17:08:34 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 16 17:08:34 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 16 17:08:34 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 16 17:12:44 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 16 17:12:44 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 16 17:12:44 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 16 17:33:16 2008] [notice] Graceful restart requested, doing restart
[Thu Oct 16 17:33:16 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 16 17:33:17 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Wed Oct 22 00:38:11 2008] [notice] caught SIGTERM, shutting down
[Wed Oct 22 00:40:39 2008] [warn] Init: Session Cache is not configured [hint: SSLSessionCache]
[Wed Oct 22 00:40:39 2008] [notice] suEXEC mechanism enabled (wrapper: /usr/lib/apache2/suexec2)
[Wed Oct 22 00:40:39 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Wed Oct 22 00:40:42 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Wed Oct 22 00:53:05 2008] [error] server reached MaxClients setting, consider raising the MaxClients setting
[Wed Oct 22 18:45:17 2008] [notice] SIGHUP received.  Attempting to restart
[Wed Oct 22 18:45:17 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Wed Oct 22 18:45:18 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Wed Oct 22 18:51:58 2008] [notice] SIGHUP received.  Attempting to restart
[Wed Oct 22 18:51:58 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Wed Oct 22 18:51:58 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Wed Oct 22 18:57:30 2008] [notice] SIGHUP received.  Attempting to restart
[Wed Oct 22 18:57:30 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Wed Oct 22 18:57:30 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Wed Oct 22 19:12:54 2008] [notice] caught SIGTERM, shutting down
[Wed Oct 22 19:14:43 2008] [warn] Init: Session Cache is not configured [hint: SSLSessionCache]
[Wed Oct 22 19:14:43 2008] [notice] suEXEC mechanism enabled (wrapper: /usr/lib/apache2/suexec2)
[Wed Oct 22 19:14:43 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Wed Oct 22 19:14:43 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Wed Oct 22 19:14:48 2008] [error] server reached MaxClients setting, consider raising the MaxClients setting
[Thu Oct 23 15:54:11 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 23 15:54:12 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 23 15:54:13 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 23 15:55:54 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 23 15:55:54 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 23 15:55:54 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 23 21:28:15 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 23 21:28:16 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 23 21:28:17 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 23 21:31:18 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 23 21:31:18 2008] [notice] mod_python: Creating 8 session mutexes based on 10 max processes and 0 max threads.
[Thu Oct 23 21:31:19 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations
[Thu Oct 23 21:39:32 2008] [notice] SIGHUP received.  Attempting to restart
[Thu Oct 23 21:39:32 2008] [notice] mod_python: Creating 8 session mutexes based on 30 max processes and 0 max threads.
[Thu Oct 23 21:39:32 2008] [notice] Apache/2.0.55 (Ubuntu) mod_python/3.2.8 Python/2.4.4c1 PHP/5.1.6 mod_ssl/2.0.55 OpenSSL/0.9.8b mod_perl/2.0.2 Perl/v5.8.8 configured -- resuming normal operations

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Accepted Solution

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Xyptilon2 earned 500 total points
ID: 22793741
These settings should be played with. I'm running MaxClients at 150 and 50 start up server, however thats on a heavy production machine. Basically make sure you have enough Apache daemons being able to handle all requests and make sure you've enough RAM to accomodate for it.

Perhaps you have an I/O bottleneck, you can determine that by looking at iostat, which may not be installed on your server, perhaps you need to install it.
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Author Closing Comment

by:andycas
ID: 31508836
Many thanks, just what I wanted. I solved my immediate problem and learnt a lot in the mean time.
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Author Comment

by:andycas
ID: 22797975
I'll have to check out iostat at some stage - it's not installed on the server at the moment.  However, raising MaxClients to 50 seems to have made a huge difference.  It's now responding well even during heavier periods of traffic.  I'm currently running the settings below and CPU and RAM are both low so I've probably got room to increase more if necessary or else start to tune MySQL too.

Thanks!
<IfModule prefork.c>
StartServers       5
MinSpareServers    5
MaxSpareServers    10
MaxClients        50
MaxRequestsPerChild  250
</IfModule>

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