# phpman > info > cachefilesd.conf

[CACHEFILESD.CONF(5)](https://www.chedong.com/phpMan.php/man/CACHEFILESD.CONF/5/markdown)          Cache Files Utilities         [CACHEFILESD.CONF(5)](https://www.chedong.com/phpMan.php/man/CACHEFILESD.CONF/5/markdown)

NAME
       /etc/cachefilesd.conf - Local file caching configuration file

SYNOPSIS
       The  configuration  file  for cachefilesd which can manage a persistent
       cache for a variety of network filesystems using a set of files  on  an
       already mounted filesystem as the data store.

DESCRIPTION
       This  configuration  file  can  contain a number of commands.  Each one
       should be on a separate line.  Blank lines and lines beginning  with  a
       '#' character are considered to be comments and are discarded.

       The only mandatory command is:

       dir <path>
              This  command specifies the directory containing the root of the
              cache.  It may only specified once per configuration file.

       All the other commands are optional:

       secctx <label>
              Specify an LSM security context as which the kernel will perform
              operations   to  access  the  cache.   The  default  is  to  use
              cachefilesd's security context.  Files will be  created  in  the
              cache  with  the  label of directory specified to the 'dir' com-
              mand.

       brun <N>%

       bcull <N>%

       bstop <N>%

       frun <N>%

       fcull <N>%

       fstop <N>%
              These commands configure the culling limits.  The  defaults  are
              7% (run), 5% (cull) and 1% (stop) respectively.  See the section
              on cache culling for more information.

              The commands beginning with a 'b' are file space (block) limits,
              those beginning with an 'f' are file count limits.

       tag <name>
              This  command specifies a tag to FS-Cache to use in distinguish-
              ing multiple caches.  This is only required  if  more  than  one
              cache is going to be used.  The default is "CacheFiles".

       culltable <log2size>
              This  command specifies the size of the tables holding the lists
              of cullable objects in the cache.  The bigger  the  number,  the
              faster and more smoothly that culling can proceed when there are
              many objects in the cache, but the more memory will be  consumed
              by cachefilesd.

              The quantity is specified as log2 of the size actually required,
              for example 12 indicates a table of 4096 entries  and  13  indi-
              cates  8192  entries.  The permissible values are between 12 and
              20, the latter indicating 1048576 entries.  The default is 12.

       nocull Disable culling.  Culling and building up the cull table take up
              a  certain  amount of a systems resources, which may be undesir-
              able.  Supplying this option disables all culling activity.  The
              cache  will  keep  building  up  to  the limits set and won't be
              shrunk, except by the removal of out-dated cache files.

       resume_thresholds <blocks> <files>
              This command specifies the amount of blocks or  files  that  the
              kernel  should  let  go  of before the daemon should resume from
              culling table scan suspension.

              Scanning to refill the cull table is suspended when all the  ob-
              jects  in a cache are pinned by a live network filesystem in the
              kernel and there's nothing to cull.

              Either value can be "-" to indicate that this  threshold  should
              be ignored.

       debug <mask>
              This command specifies a numeric bitmask to control debugging in
              the kernel module.  The default is zero (all off).  The  follow-
              ing values can be OR'd into the mask to collect various informa-
              tion:

              1      Turn on trace of function entry (_enter() macros)

              2      Turn on trace of function exit (_leave() macros)

              4      Turn on trace of internal debug points (_debug())

              This mask can also be set through /sys/module/cachefiles/parame-
              ters/debug.

EXAMPLES
       As an example, consider the following:

              dir /var/cache/fscache
              secctx cachefiles_kernel_t
              tag mycache
              brun 10%
              bcull 7%
              bstop 3%
              secctx system_u:system_r:cachefiles_kernel_t:s0

       This   places   the   cache  storage  objects  in  a  directory  called
       "/var/cache/fscache", names the cache "mycache", permits the  cache  to
       run freely as long as there's at least 10% free space on /var/cache/fs-
       cache/, starts culling the cache when the free space drops below 7% and
       stops  writing  new  stuff  into  the cache if the amount of free space
       drops below 3%.  If the cache is suspended, it won't  reactivate  until
       the amount of free space rises again to 10% or better.

       Furthermore,  this  will tell the kernel module the security context it
       should use when accessing the cache (SELinux is assumed to be  the  LSM
       in  this example).  In this case, SELinux would use cachefiles_kernel_t
       as the key into the policy.

CACHE CULLING
       The cache may need culling occasionally to make space.   This  involves
       discarding  objects  from  the  cache that have been used less recently
       than anything else.  Culling is based on the access time  of  data  ob-
       jects.  Empty directories are culled if not in use.

       Cache  culling is done on the basis of the percentage of blocks and the
       percentage of files available in the underlying filesystem.  There  are
       six "limits":

       brun

       frun   If the amount of free space and the number of available files in
              the cache rises above both these limits, then culling is  turned
              off.

       bcull

       fcull  If  the  amount  of  available  space or the number of available
              files in the cache falls below  either  of  these  limits,  then
              culling is started.

       bstop

       fstop  If  the  amount  of  available  space or the number of available
              files in the cache falls below either of these limits,  then  no
              further  allocation  of  disk  space or files is permitted until
              culling has raised things above these limits again.

       These must be configured thusly:

              0 <= bstop < bcull < brun < 100
              0 <= fstop < fcull < frun < 100

       Note that these are percentages of available space and available files,
       and  do not appear as 100 minus the percentage displayed by the df pro-
       gram.

       The userspace daemon scans the cache to build up a  table  of  cullable
       objects.   These  are  then culled in least recently used order.  A new
       scan of the cache is started as soon as space is  made  in  the  table.
       Objects  will  be skipped if their atimes have changed or if the kernel
       module says it is still using them.

       Culling can be disabled with the nocull option.

SEE ALSO
       [cachefilesd(8)](https://www.chedong.com/phpMan.php/man/cachefilesd/8/markdown), [df(1)](https://www.chedong.com/phpMan.php/man/df/1/markdown), /usr/share/doc/cachefilesd/README

AUTHORS
       David Howells <<dhowells@redhat.com>>

Linux                          14 November 2005            [CACHEFILESD.CONF(5)](https://www.chedong.com/phpMan.php/man/CACHEFILESD.CONF/5/markdown)