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 (no
  Windows)
• User homepages (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

• Utilizing resources as efficiently as possible
• Not always speed!
• Its not always a good idea
• Use with care It can break things
• Buy more hardware instead
• Helps against bottlenecks, not underpowered
  systems as a whole

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Tuning Apache (1)Make Apache do less

• Disable unused processing (pre and post)
• mod_includes
• ExtendedStatus
• Disable DNS and User lookups
• Avoid disk operations
• AllowOverride
• FollowSymlinks
• mod_disallow_uid for security

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Example

• HostNameLookups off
• UserDir /home//WWW
• AllowOverride None
• Options FollowSymlinks
• DisallowUid 0
• DisallowGid 0

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Tuning Apache (2)Make Apache wait less

• Tune process model
• MinSpareServers
• MaxSpareServers
• StartServers
• MaxClients
• MaxRequestsPerChild

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Tuning Apache (3)

• Avoid running other applications on the same
  servers
• Do not run out of memory
• Swapping kills performance
• Offload functionality
• Use a frontproxy to serve static data
• Use a frontproxy or similar to handle SSL

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Tuning Apache (4)Make Apache work smartly

• Compress data
• mod_gzip or mod_compress
• Throttle popular sites or directories
• By OS, or mod_bandwidth or mod_throttle
• For mass virtualhosting, use mod_rewrite or
  mod_vhost_alias
• Write 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
• BandwidthModule On
• ltDirectory /homegt
• Bandwidth 194.109.0.0/23 0
• Bandwidth all 1024
• MinBandwidth -1
• lt/Directorygt
• XS4ALLUserDir WWW

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Tuning Applications

• Optimize your scripts/programs
• Use a language specific interpreter-module
• mod_perl
• mod_python, mod_snake
• mod_dtcl, NeoScript, many more
• mod_php
• mod_ruby
• Use FastCGI
• Rewrite C programs directly into Apache as 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 are available at
  http//www.xs4all.nl/thomas/apachecon
• Email me at thomas_at_xs4all.net