NAME

       ureadahead - Read files in advance during boot

SYNOPSIS

       ureadahead [OPTIONS]...  [PACK]

DESCRIPTION

       ureadahead  (über-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.

OPTIONS

       --verbose
              May be used to report  on  ureadahead's  operation.   In  particular,  this  causes
              information  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.

       --daemon
              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.

       --force-trace
              Discards all pack files and forces re-tracing.

       --timeout=SECONDS
              Normally when tracing, ureadahead will  wait  for  a  TERM  or  INT  signal  before
              concluding  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.

       --sort=SORT
              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.

OTHER MOUNT POINTS

       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
       mountpoint.pack

       When tracing, these will be automatically generated.

FILES

       /var/lib/ureadahead/pack

AUTHOR

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

BUGS

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

COPYRIGHT

       Copyright © 2009 Canonical Ltd.

       This  is  free software; see the source for copying conditions.  There is NO warranty; not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       readahead(2)