Tag Archives: performance

Web Site Performance Monitoring Tools: Load Testing

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Determining the performance of web site and web applications is important. In order to create sites users want to visit they need compelling content but they also need to provide the performance users expect.

One of the wonderful aspects of creating web applications is the availability of software as a service solutions to meet your needs. These include monitoring tools and tools for testing the performance of your sites.

Image of LoadView testing - $9.99/mo + load test costs of each test

In this post I look at load testing using LoadView Stress Testing service. Tests are not cheap. The cost is $9.99 a month for an account plus the costs of each stress test you run. The next image shows the breakdown of a small stress test on this blog which cost $8.25 to

image of a small load test cost breakdown ($8.25 total)

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Basic MySQL Performance Monitoring

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Basic MySQL Performance Monitoring

regular Ubuntu cli tools

  • mysqladmin status – mysqladmin status -uroot -p

MySQL command line interface tools

[bash]mysql -uroot -p[/bash] to open the command line.

[sql]SHOW GLOBAL STATUS;
SHOW ENGINE INNODB STATUS;
SHOW PROCESSLIST;
SHOW GLOBAL STATUS LIKE ‘Qcache_%’;[/sql]

cli tools

  • mytop – top for MySQL. Install using: sudo apt-get install mytop (assuming Ubuntu operating system). There is a very useful setting file that can be used to set parameters instead of having to include them in each command. Save the file as ~/.mytop.
  • MySQLTuner – provides suggestions on performance improvements and my.cnf settings by analyzing data on your mysql database server.

Setting considerations

  • If Open_tables (SHOW GLOBAL STATUS will show this) is equal to your [bash]table_cache size[/bash] (set in /etc/mysql/my.cnf) that means it is being capped by your setting. The more MySQL has to read the table from disk the more IO and slower response, so if you have available RAM increasing the table_cache size may well make a big difference.
  • Key_reads/Key_read_request ratio should normally be < 0.01 (per MySQL manual, this means that nearly all key requests are taken from RAM). You can get both values using SHOW GLOBAL STATUS and then calculate the ratio. If the ratio is too high, consider increasing the key_buffer (in /etc/mysql/my.sql).
  • key_writes/key_writes_request should normally be near 1 (per MySQL manual)

Phusion Passenger Tips and Troubleshooting Ideas

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Some tips and troubleshooting ideas for Phusion Passenger

Phusion Passenger manages resources for rails applications – spawning new instances as needed, etc..

  • [bash]passenger-status[/bash] – provide the status of passenger rails processes

Configuring Phusion Passenger

Add lines to /etc/apache2/apache2.conf to change the default settings

  • [bash]PassengerMaxPoolSize 10[/bash] – maximum number of total rails application instances, the default is 6
  • PassengerMaxInstancesPerApp 5 – sets the maximum pool size for any 1 rails application to 10 instances (default is no limit).
  • [bash]PassengerUseGlobalQueue ON[/bash] – sets globaly queing on, it is off by default. You want globaly queuing on if your requests have large differences in response times (slow and fast responses).

Related: Passenger documentation

Troubleshooting

If you try [bash]sudo passenger-status[/bash] and get something like
*** ERROR: Cannot query status for Passenger instance 2280:
Connection refused – /tmp/passenger.2280/info/status.socket
Restarting (not reloading) apache [bash]sudo /etc/init.d/apache2 restart[/bash] may fix the problem.

System Monitoring Tools for VPS

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Tools for monitoring performance and troubleshooting Ubuntu VPS web servers

  • Munin – graphs of system resources over time. Very nice. Can be a bit difficult to setup.
  • top – system stats
  • iotop – like top, but for io stats. Install [bash]sudo apt-get install iotop[/bash] Useful setup [bash]iotop -b -o -d 30 -t[/bash] -b (batch – so you can keep a running tally of results) -o (only those processes with io) -d (delay and seconds – how often to print out stats) -t (include time in printout)
  • vmstat – stats on memory, io, swap, cpu and system. Example: [bash]vmstat 10[/bash] (prints out stats every ten seconds.
  • iostat

Error logs

  • [bash]sudo nano /var/log/apache2/error.log[/bash]

Apache web server access log statistics

  • Webalizer – [bash]sudo apt-get install webalizer[/bash] GeoIP is required for webalizer [bash]sudo apt-get install geoip-bin[/bash] detailed instructions