.\"
.\" Copyright (c) 2015-2023 Apple Inc.
.\" Licensed under the MIT License.
.\"
.Dd May 6, 2023
.Dt FSCK_APFS 8
.Os "Mac OS X"
.Sh NAME
.Nm fsck_apfs
.Nd APFS consistency check
.Sh SYNOPSIS
.Nm fsck_apfs
.Op Fl n | y
.Op Fl q
.Op Fl l
.Op Fl s
.Op Fl S
.Op Fl o
.Op Fl b Ar num
.Op Fl c
.Op Fl C
.Op Fl d
.Op Fl E Ar path
.Op Fl F | M
.Op Fl g | x
.Op Fl W
.Op Fl T
.Op Fl D
.Ar device
.Sh DESCRIPTION
The
.Nm
utility verifies and repairs APFS containers and volumes.
.Pp
.Nm
checks the specified APFS containers and volumes and tries to repair
all detected inconsistencies.
.Pp
Because of inconsistencies between the block device and the buffer
cache, the raw device should always be used.
.Pp
In its current state, fsck_apfs checks the integrity of various container
data structures.
.Pp
The options are as follows:
.Bl -hang -width filexxxx
.It Fl q
Causes
.Nm
to quickly check whether the device is `clean'. If
.Ar device
is an APFS volume,
.Nm
will quickly check the APFS container and the specified APFS volume.
If
.Ar device
is an APFS container,
.Nm
will quickly check the APFS container and all the APFS volumes in it.
By default, no repairs are attempted during a quick check.
.It Fl n
Never attempt to repair any damage that is found.
.It Fl y
Always attempt to repair any damage that is found.
.It Fl l
Enable live verification mode.
This makes it possible to check an APFS
container which is currently mounted read-write, although no
repairs can be made. Note that live verification mode may cause your system to stop responding until
.Nm
completes.
.It Fl s
Print space verification summary.
.It Fl S
Skip iteration of snapshots (top-level snapshot structures will still be checked), although no
repairs can be made.
.It Fl o
Repair overallocations; please do not run an older fsck_apfs on newer systems with this option.
.It Fl b Ar <num>
Set the default cache block size to
.Ar num
KB.
.It Fl c
Enable the gathering and printing of cache statistics.
.It Fl C
Force a sync of the container prior to freezing it in live verification mode.
.It Fl d
Print extra debugging information.
.It Fl E Ar <path>
Write warning and error summary information to
.Ar path
in addition to the standard location (/var/log/fsck_apfs_error.log).  Pass
.Ar -
to write it to stdout.
.It Fl F
Force checking of encrypted volumes, requiring the volumes to be unlocked.
.It Fl M
Skip checks requiring decryption of volume data. Unencrypted volume metadata is
still checked.
.It Fl g
Use "GUI" mode for the output.  Output is in a form suitable for parsing by
other programs.
.It Fl x
Output will be in XML.
.It Fl W
Treat warnings as fatal.  By default,
.Nm
will exit with a return code of 0 if there are warnings but no errors.  This
option will cause it to exit with an appropriate error code in that situation.
.It Fl T
Enable B-Tree node repairs.  Only used when repairing so either
.Fl y
must be present, or both
.Fl n
and
.Fl q
must be absent.
.It Fl D
When doing B-Tree node repairs, allow searching free blocks for candidate nodes.
This requires the
.Fl T
option as well.
.El
.Sh EXIT STATUS
.Nm
exits with 0 on success, and >0 if error occurs.
.Sh SEE ALSO
.Xr fsck 8
.\".Sh BUGS
.\" .Nm
.\" is not able to fix some inconsistencies that it detects.
.\".Sh HISTORY