# e2fsck.conf

## NAME



           e2fsck.conf - Configuration file for e2fsck
    


## DESCRIPTION



           _e2fsck.conf_ is the configuration file for e2fsck(8).  It controls
           the default behavior of e2fsck(8) while it is checking ext2, ext3,
           or ext4 file systems.
    
           The _e2fsck.conf_ file uses an INI-style format.  Stanzas, or top-
           level sections, are delimited by square braces: [ ].  Within each
           section, each line defines a relation, which assigns tags to
           values, or to a subsection, which contains further relations or
           subsections.  An example of the INI-style format used by this
           configuration file follows below:
    
                [section1]
                     tag1 = value_a
                     tag1 = value_b
                     tag2 = value_c
    
                [section 2]
                     tag3 = {
                          subtag1 = subtag_value_a
                          subtag1 = subtag_value_b
                          subtag2 = subtag_value_c
                     }
                     tag1 = value_d
                     tag2 = value_e
                }
    
           Comments are delimited by a semicolon (';') or a hash ('#')
           character at the beginning of the comment, and are terminated by
           the end of line character.
    
           Tags and values must be quoted using double quotes if they contain
           spaces.  Within a quoted string, the standard backslash
           interpretations apply: "\n" (for the newline character), "\t" (for
           the tab character), "\b" (for the backspace character), and "\\"
           (for the backslash character).
    
           The following stanzas are used in the _e2fsck.conf_ file.  They will
           be described in more detail in future sections of this document.
    
           _[options]_
                  This stanza contains general configuration parameters for
                  **e2fsck** 's behavior.
    
           _[defaults]_
                  Contains relations which define the default parameters used
                  by e2fsck(8).  In general, these defaults may be overridden
                  by command-line options provided by the user.
    
           _[problems]_
                  This stanza allows the administrator to reconfigure how
                  e2fsck handles various file system inconsistencies.
    
           _[scratch_files]_
                  This stanza controls when e2fsck will attempt to use
                  scratch files to reduce the need for memory.
    


## THE [options] STANZA



           The following relations are defined in the _[options]_ stanza.
    
           _allow_cancellation_
                  If this relation is set to a boolean value of true, then if
                  the user interrupts e2fsck using ^C, and the file system is
                  not explicitly flagged as containing errors, e2fsck will
                  exit with an exit status of 0 instead of 32.  This setting
                  defaults to false.
    
           _accept_time_fudge_
                  Unfortunately, due to Windows' unfortunate design decision
                  to configure the hardware clock to tick localtime, instead
                  of the more proper and less error-prone UTC time, many
                  users end up in the situation where the system clock is
                  incorrectly set at the time when e2fsck is run.
    
                  Historically this was usually due to some distributions
                  having buggy init scripts and/or installers that didn't
                  correctly detect this case and take appropriate
                  countermeasures.  Unfortunately, this is occasionally true
                  even today, usually due to a buggy or misconfigured
                  virtualization manager or the installer not having access
                  to a network time server during the installation process.
                  So by default, we allow the superblock times to be fudged
                  by up to 24 hours.  This can be disabled by setting
                  _accept_time_fudge_ to the boolean value of false.  This
                  setting defaults to true.
    
           _broken_system_clock_
                  The e2fsck(8) program has some heuristics that assume that
                  the system clock is correct.  In addition, many system
                  programs make similar assumptions.  For example, the UUID
                  library depends on time not going backwards in order for it
                  to be able to make its guarantees about issuing universally
                  unique ID's.  Systems with broken system clocks, are well,
                  broken.  However, broken system clocks, particularly in
                  embedded systems, do exist.  E2fsck will attempt to use
                  heuristics to determine if the time can not be trusted; and
                  to skip time-based checks if this is true.  If this boolean
                  is set to true, then e2fsck will always assume that the
                  system clock can not be trusted.
    
           _buggy_init_scripts_
                  This boolean relation is an alias for _accept_time_fudge_ for
                  backwards compatibility; it used to be that the behavior
                  defined by _accept_time_fudge_ above defaulted to false, and
                  _buggy_init_scripts_ would enable superblock time field to be
                  wrong by up to 24 hours.  When we changed the default, we
                  also renamed this boolean relation to _accept_time_fudge._
    
           _clear_test_fs_flag_
                  This boolean relation controls whether or not e2fsck(8)
                  will offer to clear the test_fs flag if the ext4 file
                  system is available on the system.  It defaults to true.
    
           _defer_check_on_battery_
                  This boolean relation controls whether or not the interval
                  between file system checks (either based on time or number
                  of mounts) should be doubled if the system is running on
                  battery.  This setting defaults to true.
    
           _indexed_dir_slack_percentage_
                  When e2fsck(8) repacks a indexed directory, reserve the
                  specified percentage of empty space in each leaf nodes so
                  that a few new entries can be added to the directory
                  without splitting leaf nodes, so that the average fill
                  ratio of directories can be maintained at a higher, more
                  efficient level.  This relation defaults to 20 percent.
    
           _inode_count_fullmap_
                  If this boolean relation is true, trade off using memory
                  for speed when checking a file system with a large number
                  of hard-linked files.  The amount of memory required is
                  proportional to the number of inodes in the file system.
                  For large file systems, this can be gigabytes of memory.
                  (For example a 40TB file system with 2.8 billion inodes
                  will consume an additional 5.7 GB memory if this
                  optimization is enabled.)  This setting defaults to false.
    
           _log_dir_
                  If the _log_filename_ or _problem_log_filename_ relations
                  contains a relative pathname, then the log file will be
                  placed in the directory named by the _log_dir_ relation.
    
           _log_dir_fallback_
                  This relation contains an alternate directory that will be
                  used if the directory specified by _log_dir_ is not available
                  or is not writable.
    
           _log_dir_wait_
                  If this boolean relation is true, them if the directories
                  specified by _log_dir_ or _log_dir_fallback_ are not available
                  or are not yet writable, e2fsck will save the output in a
                  memory buffer, and a child process will periodically test
                  to see if the log directory has become available after the
                  boot sequence has mounted the requested file system for
                  reading/writing.  This implements the functionality
                  provided by logsave(8) for e2fsck log files.
    
           _log_filename_
                  This relation specifies the file name where a copy of
                  e2fsck's output will be written.   If certain problem
                  reports are suppressed using the _max_count_problems_
                  relation, (or on a per-problem basis using the _max_count_
                  relation), the full set of problem reports will be written
                  to the log file.  The filename may contain various percent-
                  expressions (%D, %T, %N, etc.) which will be expanded so
                  that the file name for the log file can include things like
                  date, time, device name, and other run-time parameters.
                  See the **LOGGING** section for more details.
    
           _max_count_problems_
                  This relation specifies the maximum number of problem
                  reports of a particular type will be printed to stdout
                  before further problem reports of that type are squelched.
                  This can be useful if the console is slow (i.e., connected
                  to a serial port) and so a large amount of output could end
                  up delaying the boot process for a long time (potentially
                  hours).
    
           _no_optimize_extents_
                  If this boolean relation is true, do not offer to optimize
                  the extent tree by reducing the tree's width or depth.
                  This setting defaults to false.
    
           _problem_log_filename_
                  This relation specifies the file name where a log of
                  problem codes found by e2fsck be written.  The filename may
                  contain various percent-expressions (%D, %T, %N, etc.)
                  which will be expanded so that the file name for the log
                  file can include things like date, time, device name, and
                  other run-time parameters.  See the **LOGGING** section for
                  more details.
    
           _readahead_mem_pct_
                  Use this percentage of memory to try to read in metadata
                  blocks ahead of the main e2fsck thread.  This should reduce
                  run times, depending on the speed of the underlying storage
                  and the amount of free memory.  There is no default, but
                  see **readahead_kb** for more details.
    
           _readahead_kb_
                  Use this amount of memory to read in metadata blocks ahead
                  of the main checking thread.  Setting this value to zero
                  disables readahead entirely.  By default, this is set the
                  size of two block groups' inode tables (typically 4MiB on a
                  regular ext4 file system); if this amount is more than
                  1/50th of total physical memory, readahead is disabled.
    
           _report_features_
                  If this boolean relation is true, e2fsck will print the
                  file system features as part of its verbose reporting
                  (i.e., if the **-v** option is specified)
    
           _report_time_
                  If this boolean relation is true, e2fsck will run as if the
                  options **-tt** are always specified.  This will cause e2fsck
                  to print timing statistics on a pass by pass basis for full
                  file system checks.
    
           _report_verbose_
                  If this boolean relation is true, e2fsck will run as if the
                  option **-v** is always specified.  This will cause e2fsck to
                  print some additional information at the end of each full
                  file system check.
    


## THE [defaults] STANZA



           The following relations are defined in the _[defaults]_ stanza.
    
           _undo_dir_
                  This relation specifies the directory where the undo file
                  should be stored.  It can be overridden via the
                  **E2FSPROGS_UNDO_DIR** environment variable.  If the directory
                  location is set to the value _none_ , **e2fsck** will not create
                  an undo file.
    


## THE [problems] STANZA



           Each tag in the _[problems]_ stanza names a problem code specified
           with a leading "0x" followed by six hex digits.  The value of the
           tag is a subsection where the relations in that subsection
           override the default treatment of that particular problem code.
    
           Note that inappropriate settings in this stanza may cause **e2fsck**
           to behave incorrectly, or even crash.  Most system administrators
           should not be making changes to this section without referring to
           source code.
    
           Within each problem code's subsection, the following tags may be
           used:
    
           _description_
                  This relation allows the message which is printed when this
                  file system inconsistency is detected to be overridden.
    
           _preen_ok_
                  This boolean relation overrides the default behavior
                  controlling whether this file system problem should be
                  automatically fixed when **e2fsck** is running in preen mode.
    
           _max_count_
                  This integer relation overrides the _max_count_problems_
                  parameter (set in the options section) for this particular
                  problem.
    
           _no_ok_  This boolean relation overrides the default behavior
                  determining whether or not the file system will be marked
                  as inconsistent if the user declines to fix the reported
                  problem.
    
           _no_default_
                  This boolean relation overrides whether the default answer
                  for this problem (or question) should be "no".
    
           _preen_nomessage_
                  This boolean relation overrides the default behavior
                  controlling whether or not the description for this file
                  system problem should be suppressed when **e2fsck** is running
                  in preen mode.
    
           _no_nomsg_
                  This boolean relation overrides the default behavior
                  controlling whether or not the description for this file
                  system problem should be suppressed when a problem forced
                  not to be fixed, either because **e2fsck** is run with the **-n**
                  option or because the _force_no_ flag has been set for the
                  problem.
    
           _force_no_
                  This boolean option, if set to true, forces a problem to
                  never be fixed.  That is, it will be as if the user problem
                  responds 'no' to the question of 'should this problem be
                  fixed?'.  The _force_no_ option even overrides the **-y** option
                  given on the command-line (just for the specific problem,
                  of course).
    
           _not_a_fix_
                  This boolean option, it set to true, marks the problem as
                  one where if the user gives permission to make the
                  requested change, it does not mean that the file system had
                  a problem which has since been fixed.  This is used for
                  requests to optimize the file system's data structure, such
                  as pruning an extent tree.
    


## THE [scratch_files] STANZA



           The following relations are defined in the _[scratch_files]_ stanza.
    
           _directory_
                  If the directory named by this relation exists and is
                  writeable, then e2fsck will attempt to use this directory
                  to store scratch files instead of using in-memory data
                  structures.
    
           _numdirs_threshold_
                  If this relation is set, then in-memory data structures
                  will be used if the number of directories in the file
                  system are fewer than amount specified.
    
           _dirinfo_
                  This relation controls whether or not the scratch file
                  directory is used instead of an in-memory data structure
                  for directory information.  It defaults to true.
    
           _icount_ This relation controls whether or not the scratch file
                  directory is used instead of an in-memory data structure
                  when tracking inode counts.  It defaults to true.
    


## LOGGING



           E2fsck has the facility to save the information from an e2fsck run
           in a directory so that a system administrator can review its
           output at their leisure.  This allows information captured during
           the automatic e2fsck preen run, as well as a manually started
           e2fsck run, to be saved for posterity.  This facility is
           controlled by the _log_filename_ , _log_dir_ , _log_dir_fallback_ , and
           _log_dir_wait_ relations in the _[options]_ stanza.
    
           The filename in _log_filename_ may contain the following percent-
           expressions that will be expanded as follows.
    
           **%d** The current day of the month
    
           **%D** The current date; this is a equivalent of **%Y%m%d**
    
           **%h** The hostname of the system.
    
           **%H** The current hour in 24-hour format (00..23)
    
           **%m** The current month as a two-digit number (01..12)
    
           **%M** The current minute (00..59)
    
           **%N** The name of the block device containing the file system,
                  with any directory pathname stripped off.
    
           **%p** The pid of the e2fsck process
    
           **%s** The current time expressed as the number of seconds since
                  1970-01-01 00:00:00 UTC
    
           **%S** The current second (00..59)
    
           **%T** The current time; this is equivalent of **%H%M%S**
    
           **%u** The name of the user running e2fsck.
    
           **%U** This percent expression does not expand to anything, but it
                  signals that any following date or time expressions should
                  be expressed in UTC time instead of the local timezone.
    
           **%y** The last two digits of the current year (00..99)
    
           **%Y** The current year (i.e., 2012).
    


## EXAMPLES



           The following recipe will prevent e2fsck from aborting during the
           boot process when a file system contains orphaned files.  (Of
           course, this is not always a good idea, since critical files that
           are needed for the security of the system could potentially end up
           in lost+found, and starting the system without first having a
           system administrator check things out may be dangerous.)
    
                [problems]
                     0x040002 = {
                          preen_ok = true
                          description = "@u @i %i.  "
                     }
    
           The following recipe will cause an e2fsck logfile to be written to
           the directory /var/log/e2fsck, with a filename that contains the
           device name, the hostname of the system, the date, and time: e.g.,
           "e2fsck-sda3.server.INFO.20120314-112142".  If the directory
           containing /var/log is located on the root file system which is
           initially mounted read-only, then the output will be saved in
           memory and written out once the root file system has been
           remounted read/write.   To avoid too much detail from being
           written to the serial console (which could potentially slow down
           the boot sequence), only print no more than 16 instances of each
           type of file system corruption.
    
                [options]
                     max_count_problems = 16
                     log_dir = /var/log/e2fsck
                     log_filename = e2fsck-%N.%h.INFO.%D-%T
                     log_dir_wait = true
    


## FILES



           _/etc/e2fsck.conf_
                  The configuration file for e2fsck(8).
    


* * *