below apache2ctl status with almost no users online.
For over 5 years we (cloud ERP supplier) deploy instances on Google Cloud with Apache with mod_perl.
This week our largest server became slow and unresponsive. No idle workers were available. It turned out increasing both MaxRequestWorkers and ServerLimit to 400 from 150 in mpm_prefork.conf got our server back fast.
I’m wondering why many requests stay in "R" Reading Request, at least 10 times more requests then actually should be.
We did further checking, DoS does not seem to be the issue, as also other servers – in different clouds as ASW or Alibaba – we notice the same ratio of 10 between requests actually being processed (R/W/K) and requests that stay in Reading mode.
What could cause this?
sudo /usr/sbin/apache2ctl status
Apache Server Status for localhost (via 127.0.0.1)
Server Version: Apache/2.4.7 (Ubuntu) PHP/5.5.9-1ubuntu4.29 OpenSSL/1.0.1f
mod_perl/2.0.8 Perl/v5.18.2
Server MPM: prefork
Server Built: Apr 3 2019 18:04:25
Current Time: Saturday, 29-Feb-2020 10:15:35 CET
Restart Time: Thursday, 27-Feb-2020 09:45:48 CET
Parent Server Config. Generation: 1
Parent Server MPM Generation: 0
Server uptime: 2 days 29 minutes 47 seconds
Server load: 0.75 0.77 0.75
Total accesses: 1581181 - Total Traffic: 8.6 GB
CPU Usage: u30.32 s9.64 cu0 cs0 - .0229% CPU load
9.06 requests/sec - 51.5 kB/second - 5.7 kB/request
96 requests currently being processed, 9 idle workers
RRKRRRK_RKRKKRRRRRK_RRRRKRCK_RRRC_CKK_KCRKCRK_RCR__CKKCCRCRRRRRR
RRRRR.RRRKRRRKRRR_RR..R.K.RCRKR.CKK.RRKKR.W.RRKR.....RR.........
................................................................
................................................................
................................................................
................................................................
................
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
I am hosting multiple sites on a server with 7.5gb RAM. Using apache2 mpm_prefork.
Following command gives me a value of 200-300 in production
ps aux|grep -c 'apache2'
Using top i see only some hundred megabytes of RAM is free. Error log show nothing unusual. Is this much apache2 process normal?
MaxRequestWorkers is set to 512
Update:
Now i am using mod-status to check apache activity.
I have a row like this
Srv PID Acc M CPU SS Req Conn Child Slot Client VHost Request
0-0 29342 2/2/70 W 0.07 5702 0 3.0 0.00 1.67 XXX XXX /someurl
If i check again after sometime PID not changes and i get SS with greater value that previous time. M of this request is in 'W` sending reply state. So that means apache2 process locked in for that request?
On my VPS and root servers, the situation is partially similar. AFAIK the os tries to distribute most of the processing power/RAM to running processes and frees the resources for other processes as the need arises.
Can someone please walk me through the process of how I can load test my website using apache bench tool (ab)?
I want to know the following:
How many people per minute can the site handle?
Please walk me through the commands I should run to figure this out.
I tried every tutorial, and they are confusing.
The Apache benchmark tool is very basic, and while it will give you a solid idea of some performance, it is a bad idea to only depend on it if you plan to have your site exposed to serious stress in production.
Having said that, here's the most common and simplest parameters:
-c: ("Concurrency"). Indicates how many clients (people/users) will be hitting the site at the same time. While ab runs, there will be -c clients hitting the site. This is what actually decides the amount of stress your site will suffer during the benchmark.
-n: Indicates how many requests are going to be made. This just decides the length of the benchmark. A high -n value with a -c value that your server can support is a good idea to ensure that things don't break under sustained stress: it's not the same to support stress for 5 seconds than for 5 hours.
-k: This does the "KeepAlive" funcionality browsers do by nature. You don't need to pass a value for -k as it it "boolean" (meaning: it indicates that you desire for your test to use the Keep Alive header from HTTP and sustain the connection). Since browsers do this and you're likely to want to simulate the stress and flow that your site will have from browsers, it is recommended you do a benchmark with this.
The final argument is simply the host. By default it will hit http:// protocol if you don't specify it.
ab -k -c 350 -n 20000 example.com/
By issuing the command above, you will be hitting http://example.com/ with 350 simultaneous connections until 20 thousand requests are met. It will be done using the keep alive header.
After the process finishes the 20 thousand requests, you will receive feedback on stats. This will tell you how well the site performed under the stress you put it when using the parameters above.
For finding out how many people the site can handle at the same time, just see if the response times (means, min and max response times, failed requests, etc) are numbers your site can accept (different sites might desire different speeds). You can run the tool with different -c values until you hit the spot where you say "If I increase it, it starts to get failed requests and it breaks".
Depending on your website, you will expect an average number of requests per minute. This varies so much, you won't be able to simulate this with ab. However, think about it this way: If your average user will be hitting 5 requests per minute and the average response time that you find valid is 2 seconds, that means that 10 seconds out of a minute 1 user will be on requests, meaning only 1/6 of the time it will be hitting the site. This also means that if you have 6 users hitting the site with ab simultaneously, you are likely to have 36 users in simulation, even though your concurrency level (-c) is only 6.
This depends on the behavior you expect from your users using the site, but you can get it from "I expect my user to hit X requests per minute and I consider an average response time valid if it is 2 seconds". Then just modify your -c level until you are hitting 2 seconds of average response time (but make sure the max response time and stddev is still valid) and see how big you can make -c.
Please walk me through the commands I should run to figure this out.
The simplest test you can do is to perform 1000 requests, 10 at a time (which approximately simulates 10 concurrent users getting 100 pages each - over the length of the test).
ab -n 1000 -c 10 -k -H "Accept-Encoding: gzip, deflate" http://www.example.com/
-n 1000 is the number of requests to make.
-c 10 tells AB to do 10 requests at a time, instead of 1 request at a time, to better simulate concurrent visitors (vs. sequential visitors).
-k sends the KeepAlive header, which asks the web server to not shut down the connection after each request is done, but to instead keep reusing it.
I'm also sending the extra header Accept-Encoding: gzip, deflate because mod_deflate is almost always used to compress the text/html output 25%-75% - the effects of which should not be dismissed due to it's impact on the overall performance of the web server (i.e., can transfer 2x the data in the same amount of time, etc).
Results:
Benchmarking www.example.com (be patient)
Completed 100 requests
...
Finished 1000 requests
Server Software: Apache/2.4.10
Server Hostname: www.example.com
Server Port: 80
Document Path: /
Document Length: 428 bytes
Concurrency Level: 10
Time taken for tests: 1.420 seconds
Complete requests: 1000
Failed requests: 0
Keep-Alive requests: 995
Total transferred: 723778 bytes
HTML transferred: 428000 bytes
Requests per second: 704.23 [#/sec] (mean)
Time per request: 14.200 [ms] (mean)
Time per request: 1.420 [ms] (mean, across all concurrent requests)
Transfer rate: 497.76 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.1 0 1
Processing: 5 14 7.5 12 77
Waiting: 5 14 7.5 12 77
Total: 5 14 7.5 12 77
Percentage of the requests served within a certain time (ms)
50% 12
66% 14
75% 15
80% 16
90% 24
95% 29
98% 36
99% 41
100% 77 (longest request)
For the simplest interpretation, ignore everything BUT this line:
Requests per second: 704.23 [#/sec] (mean)
Multiply that by 60, and you have your requests per minute.
To get real world results, you'll want to test Wordpress instead of some static HTML or index.php file because you need to know how everything performs together: including complex PHP code, and multiple MySQL queries...
For example here is the results of testing a fresh install of Wordpress on the same system and WAMP environment (I'm using WampDeveloper, but there are also Xampp, WampServer, and others)...
Requests per second: 18.68 [#/sec] (mean)
That's 37x slower now!
After the load test, there are a number of things you can do to improve the overall performance (Requests Per Second), and also make the web server more stable under greater load (e.g., increasing the -n and the -c tends to crash Apache), that you can read about here:
Load Testing Apache with AB (Apache Bench)
Steps to set up Apache Bench(AB) on windows (IMO - Recommended).
Step 1 - Install Xampp.
Step 2 - Open CMD.
Step 3 - Go to the apache bench destination (cd C:\xampp\apache\bin) from CMD
Step 4 - Paste the command (ab -n 100 -c 10 -k -H "Accept-Encoding: gzip, deflate" http://localhost:yourport/)
Step 5 - Wait for it. Your done
Load testing your API by using just ab is not enough. However, I think it's a great tool to give you a basic idea how your site is performant.
If you want to use the ab command in to test multiple API endpoints, with different data, all at the same time in background, you need to use "nohup" command. It runs any command even when you close the terminal.
I wrote a simple script that automates the whole process, feel free to use it: http://blog.ikvasnica.com/entry/load-test-multiple-api-endpoints-concurrently-use-this-simple-shell-script
I was also curious if I can measure the speed of my script with apache abs or a construct / destruct php measure script or a php extension.
the last two have failed for me: they are approximate.
after which I thought to try "ab" and "abs".
the command "ab -k -c 350 -n 20000 example.com/" is beautiful because it's all easier!
but did anyone think to "localhost" on any apache server for example www.apachefriends.org?
you should create a folder such as "bench" in root where you have 2 files: test "bench.php" and reference "void.php".
and then: benchmark it!
bench.php
<?php
for($i=1;$i<50000;$i++){
print ('qwertyuiopasdfghjklzxcvbnm1234567890');
}
?>
void.php
<?php
?>
on your Desktop you should use a .bat file(in Windows) like this:
bench.bat
"c:\xampp\apache\bin\abs.exe" -n 10000 http://localhost/bench/void.php
"c:\xampp\apache\bin\abs.exe" -n 10000 http://localhost/bench/bench.php
pause
Now if you pay attention closely ...
the void script isn't produce zero results !!!
SO THE CONCLUSION IS: from the second result the first result should be decreased!!!
here i got :
c:\xampp\htdocs\bench>"c:\xampp\apache\bin\abs.exe" -n 10000 http://localhost/bench/void.php
This is ApacheBench, Version 2.3 <$Revision: 1826891 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking localhost (be patient)
Completed 1000 requests
Completed 2000 requests
Completed 3000 requests
Completed 4000 requests
Completed 5000 requests
Completed 6000 requests
Completed 7000 requests
Completed 8000 requests
Completed 9000 requests
Completed 10000 requests
Finished 10000 requests
Server Software: Apache/2.4.33
Server Hostname: localhost
Server Port: 80
Document Path: /bench/void.php
Document Length: 0 bytes
Concurrency Level: 1
Time taken for tests: 11.219 seconds
Complete requests: 10000
Failed requests: 0
Total transferred: 2150000 bytes
HTML transferred: 0 bytes
Requests per second: 891.34 [#/sec] (mean)
Time per request: 1.122 [ms] (mean)
Time per request: 1.122 [ms] (mean, across all concurrent requests)
Transfer rate: 187.15 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.3 0 1
Processing: 0 1 0.9 1 17
Waiting: 0 1 0.9 1 17
Total: 0 1 0.9 1 17
Percentage of the requests served within a certain time (ms)
50% 1
66% 1
75% 1
80% 1
90% 1
95% 2
98% 2
99% 3
100% 17 (longest request)
c:\xampp\htdocs\bench>"c:\xampp\apache\bin\abs.exe" -n 10000 http://localhost/bench/bench.php
This is ApacheBench, Version 2.3 <$Revision: 1826891 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking localhost (be patient)
Completed 1000 requests
Completed 2000 requests
Completed 3000 requests
Completed 4000 requests
Completed 5000 requests
Completed 6000 requests
Completed 7000 requests
Completed 8000 requests
Completed 9000 requests
Completed 10000 requests
Finished 10000 requests
Server Software: Apache/2.4.33
Server Hostname: localhost
Server Port: 80
Document Path: /bench/bench.php
Document Length: 1799964 bytes
Concurrency Level: 1
Time taken for tests: 177.006 seconds
Complete requests: 10000
Failed requests: 0
Total transferred: 18001600000 bytes
HTML transferred: 17999640000 bytes
Requests per second: 56.50 [#/sec] (mean)
Time per request: 17.701 [ms] (mean)
Time per request: 17.701 [ms] (mean, across all concurrent requests)
Transfer rate: 99317.00 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.3 0 1
Processing: 12 17 3.2 17 90
Waiting: 0 1 1.1 1 26
Total: 13 18 3.2 18 90
Percentage of the requests served within a certain time (ms)
50% 18
66% 19
75% 19
80% 20
90% 21
95% 22
98% 23
99% 26
100% 90 (longest request)
c:\xampp\htdocs\bench>pause
Press any key to continue . . .
90-17= 73 the result i expect !
Steps to perform:
Commands For load testing
Step 1 - Install Xampp.
Step 2 - Open CMD.
Step 3 - Go to the Apache bench destination (cd C:\xampp\apache\bin) from CMD.
Step 4 - Paste the command
ab -n 100 -c 10 -k -H "Accept-Encoding: gzip, deflate" http://localhost:port/
Step 5 - Wait for it. You're done
Main Command Only “Get”
ab -k -c 25 -n 2000 http://192.168.1.113:3001/api/v1/filters/3
One of the best solution for post request load testing. Click here
My goal is to implement APC for opcode cache for a drupal 6 production site.
I have so far tested APC with several php files with and without including other php files with include_once.
Also tried to tweak the apc.ini values for shm_size, apc.include_once_override and apc.stat.
Restarted apache every time.
Resulting in apc.php not showing any changes in any values. (except of course the changed apc.ini values are shown as they should)
Every time i refresh the apc.php test page, the start time resets as the current time showing uptime 0 minutes.
apc.php -testpage shows:
General Cache InformationAPC Version 3.1.9
PHP Version 5.2.10
APC Host xxxx.xx.xx
Server Software Apache/2.2.3 (CentOS)
Shared Memory 1 Segment(s) with 128.0 MBytes
(mmap memory, pthread mutex Locks locking)
Start Time 2011/07/26 11:53:56
Uptime 0 minutes
File Upload Support 1
Cached Files 0 ( 0.0 Bytes)
Hits 1
Misses 1
Request Rate (hits, misses) 2.00 cache requests/second
Hit Rate 1.00 cache requests/second
Miss Rate 1.00 cache requests/second
Insert Rate 0.00 cache requests/second
Cache full count 0
Cached Variables 0 ( 0.0 Bytes)
Hits 0
Misses 0
Request Rate (hits, misses) 0.00 cache requests/second
Hit Rate 0.00 cache requests/second
Miss Rate 0.00 cache requests/second
Insert Rate 0.00 cache requests/second
Cache full count 0
apc.cache_by_default 1
apc.canonicalize 1
apc.coredump_unmap 0
apc.enable_cli 0
apc.enabled 1
apc.file_md5 0
apc.file_update_protection 2
apc.filters
apc.gc_ttl 3600
apc.include_once_override 0
apc.lazy_classes 0
apc.lazy_functions 0
apc.max_file_size 16
apc.mmap_file_mask /tmp/apcphp5.095eRm
apc.num_files_hint 1024
apc.preload_path
apc.report_autofilter 0
apc.rfc1867 0
apc.rfc1867_freq 0
apc.rfc1867_name APC_UPLOAD_PROGRESS
apc.rfc1867_prefix upload_
apc.rfc1867_ttl 3600
apc.serializer default
apc.shm_segments 1
apc.shm_size 128M
apc.slam_defense 0
apc.stat 0
apc.stat_ctime 0
apc.ttl 7200
apc.use_request_time 1
apc.user_entries_hint 4096
apc.user_ttl 7200
apc.write_lock 1
Host Status Diagrams:
Free: 128.0 MBytes (100.0%) Hits: 1 (50.0%)
Used: 20.3 KBytes (0.0%) Misses: 1 (50.0%)
Detailed Memory Usage and Fragmentation:
Fragmentation: 0%
phpinfo shows:
Server API CGI/FastCGI
APC:
Version 3.1.9
APC Debugging Enabled
MMAP Support Enabled
MMAP File Mask /tmp/apcphp5.JkKDk7
Locking type pthread mutex Locks
Serialization Support php
Revision $Revision: 308812 $
Build Date Jul 21 2011 14:31:12
I followed these steps to find if suexec settings would prevent caching:
http://www.litespeedtech.com/support/forum/showthread.php?t=4189
[root#host /]# ps -ef|grep lsphp
root 20402 17833 0 11:21 pts/0 00:00:00 grep lsphp
[root#host /]# ps -waux
root 17833 0.0 0.1 5004 1484 pts/0 S 10:39 0:00 bash
..indicates that there is no lsphp running on the host
also I read the following article and comments, concluding that in my case the problem is not the suexec as the user apache is the httpd process owner
http://www.brandonturner.net/blog/2009/07/fastcgi_with_php_opcode_cache/
also suexec command is not recognized when logged and launced as root # host
also i'm almost confident that there is no cPanel running on the host to check if a setting there would reset the running cache process at some interval
This leaves me with few clues where to head next.
I tried to set (with chown and chgrp) apache as the owner of the apc.php file and some test php files resulting in 500 server error.
Is there a way to check if the file permissions prevent the apc stay running?
I'm tremendously grateful for any suggestions or help.
Can you give your php.ini settings for APC ?
You must restart httpd to take setting change into account.
Try to change max file size
apc.max_file_size = 20M
You are alowing 128M of ram, it's quite low for big php applications like we have today (a single wordpress uses 32M)
apc.shm_size 128M
increase it also
I have Apache + Tomcat setup with mod_jk on 2 servers. Each server has its own Apache+Tomcat pair, and every request is being served by Tomcat load balancing workers on 2 servers.
I have a question about how Apache's maxClient and Tomcat's maxThread should be set.
The default numbers are,
Apache: maxClient=150, Tomcat: maxThread=200
In this configuration, if we have only 1 server setup, it would work just fine as Tomcat worker never receives the incoming connections more than 150 at once. However, if we are load balancing between 2 servers, could it be possible that Tomcat worker receives 150 + (some number from another server) and make the maxThread overflow as SEVERE: All threads (200) are currently busy?
If so, should I set Tomcat's maxThread=300 in this case?
Thanks
Setting maxThreads to 300 should be fine - there are no fixed rules. It depends on whether you see any connections being refused.
Increasing too much causes high memory consumption but production Tomcats are known to run with 750 threads. See here as well. http://java-monitor.com/forum/showthread.php?t=235
Have you actually got the SEVERE error? I've tested on our Tomcat 6.0.20 and it throws an INFO message when the maxThreads is crossed.
INFO: Maximum number of threads (200) created for connector with address null and port 8080
It does not refuse connections until the acceptCount value is crossed. The default is 100.
From the Tomcat docs http://tomcat.apache.org/tomcat-5.5-doc/config/http.html
The maximum queue length for incoming
connection requests when all possible
request processing threads are in use.
Any requests received when the queue
is full will be refused. The default
value is 100.
The way it works is
1) As the number of simultaneous requests increase, threads will be created up to the configured maximum (the value of the maxThreads attribute).
So in your case, the message "Maximum number of threads (200) created" will appear at this point. However requests will still be queued for service.
2) If still more simultaneous requests are received, they are queued up to the configured maximum (the value of the acceptCount attribute).
Thus a total of 300 requests can be accepted without failure. (assuming your acceptCount is at default of 100)
3) Crossing this number throws Connection Refused errors, until resources are available to process them.
So you should be fine until you hit step 3