25 Apache Performance Tips

25 Apache Performance Tips
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25 Apache Performance Tuning Tipswww.monitis.com Uptime & Device Monitoring
1. Remove unused modules
Save memory by not loading modules that aren’t needed,
including (but not limited to)…
… mod_php,
… mod_ruby,
… mod_perl,
etc.

2. Use mod_disk_cache and NOT
mod_mem_cache
Mod_mem_cachewill not share its cache amongst different
apache processes, which results in high memory usage with
little performance gain. On an active server mod_mem_cache
will rarely serve the same page twice in the same Apache
process.

3. Configure mod_disk_cache with a
flat hierarchy
Make sure you are using CacheDirLength=2and
CacheDirLevels=1to ensure htcachecleanwill not take forever
when cleaning up your cache directory.

4. Setup appropriate Expires, Etag,
and Chache-Control headers
In order to utilize your cache you have to specify when a file
expires, otherwise your client will not experience the caching
benefits.

5. Put the cache on a separate disk
Move your cache to a separate physical disk for the fastest
access without slowing down other processes.

6. Use piped logging instead of
direct logging
Directly logging to a file results in issues when rotating the log
file. A restart will be necessary to use the next log file. This
causes significant slowness for you users during the restart.
Particularly if you are using Passenger or some other app
loader.

7. Log to a different disk than the
disk serving pages
Put your logs on physically different disks than the files you
are serving.

8. Utilize mod_gzip/mod_deflate
Gzip your content before sending it off. The client will ungzip
upon receipt which will minimize the size of file transfers. Also,
it will generally improve the user experience.

9. Turn off HostnameLookups
Stop doing effortful DNS lookups. You will rarely ever need
them and when you do, you can always look them up when
really needed.

10. Avoid using hostname in configs
If HostnameLookups are turned off, it will keep you from
waiting for the DNS resolving the hostnames in your configs.
Instead, use IP addresses.

11. Use persistent connections
Set KeepAlive, KeepAliveTimeout and KeepAliveRequests.
KeepAliveTimeout defines how long Apache will wait for the
next request, and KeepAliveRequests defines the maximum
number of requests for a client prior to resetting the
connection. This will prevent the client from having to
reconnect between each request.

12. Do not set KeepAliveTimeout too
high
If you have more requests than Apache children, settings
which are set too high could exhaust your pool of available
clients.

13. Disable .htaccess
I.e. AllowOverride None. This will keep Apache from checking
for an .htaccess file upon each request.

14. Allow symlinks
I.e. Options + FoolowSymLinks – SymLinksIfOwnerMatch.
Otherwise, Apache will make a separate call on each filename
to ensure it is not a symlink.

15. Set ExtendStatus off
Although very useful, the ExtendStatus will produce several
system calls for each request to gather statistics. It‘s better to
only define a certain time frame in order to benchmark and
keep it turned off the remainder of the time.

16. Avoid Wildcards in
DirectoryIndex
Use a specific DirectoryIndex, i.e. index.html or index.php, not
index.

17. Increase Swappiness
Particularly on single site hosts this will increase the
performance. On Linux systems increase
/proc/sys/vm/swappiness to at least 60 if not higher. This will
result in loading as many files as possible into the memory
cache for a quicker access.

18. Increase Write Buffer Size
Increase your write buffer size for TCP/IP buffers. On Linux
systems increase /proc/sys/net/core/wmem_max and
/proc/sys/net/core/wmem_default. If your pages fit within this
buffer, Apache will complete a process in just one call to the
TCP/IP buffer.

19. Increase Max Open Files
If you are handling high loads, increase the number of
allowed open files. On Linux increase /proc/sys/fs/file-max
and run ulimit –H –n 4096.

20. Setup a frontend proxy for
images and stylesheets
Allow your main web servers to process the application while
images and stylesheets are served from frontend webservers.

21. Use mod_passenger for rails
Mod_passenger is able to share memory and resources
amongst several processes, allowing for faster spawning of
new application instances. It will also monitor these
processes and remove them when they become unncessary.

23. Don‘t use threaded mpm with
mod_php
Look at using mod_itk, mod_php tends to segfault with
threaded mpm.

24. Flush buffers early for pre-
render
It takes a relatively long time to create a webpage on the
backend. Flush your buffer prior to page completion to send
a partial page to the client, so it can start rendering. A good
place to do this is right after the HEAD section – so that the
browser can start fetching other objects.

25. Use a cache for frequently
accessed data
Memcached is a great for frequently used data and sessions. It
will speed up your Apache render time as databases are
slow.

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25 Apache Performance Tips

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