e2fsck.conf - Configuration file for e2fsck
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 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 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.
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 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.
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).
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
- /etc/e2fsck.conf
- The configuration file for e2fsck(8).
e2fsck(8)