/usr/share/doc/samhain/manual.html/performance-tuning.html

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><A
NAME="PERFORMANCE-TUNING"
>5.19. Performance tuning</A
></H1
><P
>  File checking is basically I/O-limited, i.e. typically most of the
  time the application waits for data from the disk. Most of the
  application runtime is spent in the checksum algorithm, but as the
  application is I/O-limited, using a faster algorithm does not neccessarily
  result in any noticable speed improvement.</P
><P
>  Logging can be very expensive, so you should avoid enabling many different
  logging facilities. You should also avoid low logging thresholds (info/debug)
  on production systems &mdash; it tends to drown real problems in the noise
  of purely informational messages, and reduces performance quite noticably.</P
><P
>  Other things you can do are:</P
><P
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><P
>        Build a static binary (use 
        the <B
CLASS="COMMAND"
>--enable-static</B
> switch for
	configure). Static binaries are faster, and also more secure,
	because they cannot be subverted via libc. 
  </P
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> 
	Unfortunately
	this is not possible on Solaris. 
	This is not a bug in <SPAN
CLASS="APPLICATION"
>samhain</SPAN
>,
	but is because some functions in Solaris are only supplied by
	dynamic libraries.
	</P
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>         Change the compiler switches to optimize more aggressively.
  </P
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>        If on a commercial UNIX, check whether the native compiler produces
	faster code (you need an ANSI C compiler). 
	The  <B
CLASS="COMMAND"
>./configure</B
> script honours 
	CC (compiler) and CFLAGS
        environment variables.
  </P
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>  On the other side, if you want to reduce the load caused by file checking,
  you can change the scheduling priority 
  (see <B
CLASS="COMMAND"
>man nice</B
>), and/or limit
  the I/O:
  <PRE
CLASS="PROGRAMLISTING"
>  [Misc]
  # low priority (positive argument means lower priority)
  SetNiceLevel=19 
  # kilobytes per second
  SetIOLimit=1000
  </PRE
></P
><P
>  If you want to avoid thrashing the file cache, you can
  tell samhain to drop checksummed files from the cache (unless they were 
  already cached). For performance reasons, this defaults to 'false'.
  <PRE
CLASS="PROGRAMLISTING"
>  [Misc]
  # drop checksummed files from cache
  SetDropCache = True
  </PRE
></P
><P
>  Similarly, for the SUID check, you can limit the files per seconds:

  <PRE
CLASS="PROGRAMLISTING"
>  [SuidCheck]  
  # limit on files per seconds
  SuidCheckFps=250 
  </PRE
>&#13;</P
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samhain 3.1.0-5ubuntu1 / usr / share / doc / samhain / manual.html / performance-tuning.html
