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ureadahead(8)									    ureadahead(8)

       ureadahead - Read files in advance during boot

       ureadahead [OPTIONS]...	[PACK]

       ureadahead  (uber-readahead) is used during boot to read files in advance of when they are
       needed such that they are already in the page cache, improving boot performance.

       When started without any arguments, it checks for the existance and  age  of  the  default
       pack file /var/lib/ureadahead/pack, and if not present or older than a month, will discard
       it and retrace the boot sequence.  The pack will then contain information about the  files
       opened during boot, and the blocks that were in memory at the completion of the boot.

       If  the	file  exists and is newer than a month old, or an alternate PACK path is given on
       the command-line, the files listed in the pack are opened and the  blocks  read	into  the
       page cache using the readahead(2) system call.

       Pack  files  are  automatically optimised for Solid-State Disks or rotational Hard Drives,
       depending on which you have.

	      May be used to report on ureadahead's operation.	In particular, this causes infor-
	      mation  about  the  size	of the pack file to be output when reading and a complete
	      dump of the contents of the pack file after tracing.

	      Places ureadahead into the background once the pack file has  been  read,  or  once
	      tracing has been enabled.

	      This  is	ignored  when reading on rotational hard drives, since it's important for
	      performance reasons not to contend with other processes for I/O.

	      Discards all pack files and forces re-tracing.

	      Normally when tracing, ureadahead will wait for a TERM or INT  signal  before  con-
	      cluding  and  generating	the  pack file.  This option instead sets a timeout after
	      which tracing is terminated.

       --dump Dump the contents of the pack file to standard output in a pretty format, does  not
	      trace or read the contents into memory.

	      Used with --dump to sort the output.

	      The  default is open, which is the order that the files will be opened.  path sorts
	      by path name, disk sorts by on-disk location, and size sorts by the amount of  data
	      that will be read for that file.

       PACK  need  not be the filename of a pack, instead it may be the name of a mount point (or
       indeed any non-file within the filesystem), in which case the pack for that device is read
       instead.  This allows ureadahead to be called in the style ureadahead /usr for filesystems
       split across multiple devices.

       Pack files for these other devices are also stored under /var/lib/ureadahead and are named

       When tracing, these will be automatically generated.


       Written by Scott James Remnant <scott@netsplit.com>

       Report bugs at <https://launchpad.net/ubuntu/+source/ureadahead/+bugs>

       Copyright (C) 2009 Canonical Ltd.

       This  is  free software; see the source for copying conditions.	There is NO warranty; not


ureadahead				    2009-09-29				    ureadahead(8)
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