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 filesystems.
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 filesystem 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 filesystem 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 filesystem is available on the
system. It defaults to true.
- defer_check_on_battery
- This boolean relation controls whether or not the interval between
filesystem 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 filesystem); 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 filesystem
inconsistency is detected to be overridden.
- preen_ok
- This boolean relation overrides the default behavior controlling whether
this filesystem 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 filesystem 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 filesystem 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 filesystem 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 filesystem 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 filesystem 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).