Performance Tuning Apache

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Performance Tuning Apache

• Thomas Wouters
• XS4ALL
• thomas_at_xs4all.net

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Overview

• Background
• What is performance tuning
• Tuning Apache
• Tuning Applications
• Tuning the Operating System(s)
• Questions

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Background

• Apache (1.x) on BSDI, FreeBSD and Linux (and no
  MS Windows)
• User sites (www.xs4all.nl/user)
• Large-scale virtualhosting
• Dedicated, high-availability servers
• NFS storage for data
• Layer-4 Ethernet switches for loadbalancing and
  fallback

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What is performance tuning

• Its about utilizing resources as efficiently as
  possible
• It isnt always about speed!
• Its not always a good idea
• Use with care It can break things
• Buy more hardware instead
• Use it to remove or work around bottlenecks, not
  underpowered systems as a whole

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Tuning Apache (1)Make Apache do less

• Disable unused pre- and post-processing, like
  mod_includes, mod_speling, and complicated
  mod_log_config directives
• Disable (or only selectively enable)
  AllowOverride, DNS lookups, ExtendedStatus and
  enable FollowSymlinks
• Especially over NFS, avoid unnecessary file
  operations like the plague

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Example

• HostNameLookups off
• UserDir /home//WWW
• DisallowUid 0
• DisallowGid 0
• ltDirectory /homegt
• AllowOverride None
• Options FollowSymlinks
• lt/Directorygt

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Tuning Apache (2)Make Apache wait less

• Tune StartServers, MinSpareServers,
  MaxSpareServers and MaxClients to avoid forking
  processes
• Avoid running other applications on the same
  server(s)
• Take care not to run out of memory swapping
  killls performance
• Use a front-proxy to cache the results of common
  requests

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Tuning Apache (3)Make Apache work smartly

• Compress data before sending it out with mod_gzip
• Manage popular virtualhosts or directories with
  mod_bandwidth or mod_throttle
• For mass virtualhosting, use mod_rewrite or
  mod_vhost_alias to collapse the configuration
  tree
• Write your own site-specific modules, or adapt
  existing ones

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Example

• mod_gzip_enable Yes
• mod_gzip_item_include mime text/.
• mod_gzip_item_exclude mime text/compressed
• UserDirXS4ALL WWW
• BandwidthModule On
• ltDirectory /mp3gt
• Bandwidth xs4all.net 0
• Bandwidth all 1024
• MinBandwidth -1
• lt/Directorygt

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Tuning Applications

• Optimize your scripts/programs -)
• Redo your scripts to use mod_perl, mod_python,
  mod_snake or your favorite language module
• Rewrite your scripts to use FastCGI
• Embed your C programs directly into Apache by
  making them a module

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Tuning the Operating System

• Free up memory
• Raise process limits (for Apache)
• Disable process accounting
• Tune the kernel (maxproc, shmem, maxfd, TCP
  stack)
• When possible, disable atime updates
• Choose the best accept-serializing strategy (in
  Apache 2.0, choose the best MPM)

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Questions ?

• These slides will be available from
  http//www.xs4all.nl/thomas/apachecon
• Email me at thomas_at_xs4all.net