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)