.\" Copyright (c) 2010-2011 Apple Inc.  All rights reserved.
.\"
.Dd July 22, 2011
.Dt FSCK_CS 8
.Os OS X
.Sh NAME
.Nm fsck_cs
.Nd verify and repair CoreStorage logical volume groups
.Sh SYNOPSIS
.Nm
.Fl q
.Ar device ...
.Nm
.Fl p
.Ar device ...
.Nm
.Op Fl y | n
.Op Fl x | g
.Op Fl l Ar logfile
.Ar device ...
.Sh DESCRIPTION
.Pp
The
.Nm
utility verifies and repairs
.Tn CoreStorage
logical volume group metadata.
.Pp
The
.Ar device
parameter(s) should be path(s) to the "raw" (character special) disk device(s) such as
.Pa /dev/rdisk1s1 
that constitute the CoreStorage logical volume group.
If you specify a "non-raw" (block special) path such as
.Pa /dev/disk1s1 ,
or just the disk name such as
.Pa disk1s1 ,
it will automatically be converted to the corresponding raw disk device
.Pa ( /dev/rdisk1s1 ) .
.Pp
The options are as follows:
.Bl -tag -offset indent
.It Fl q
Performs a "quick" check and indicates if any corruptions were
found via the exit status.  In this mode stale MLV segments are not
checked, nor is proactive MLV mirror scrubbing performed.
.It Fl p
Operates in "preen" mode.  MLV mirror blocks are repaired where
necessary.  Newer transactions may be invalidated to force a
roll-back to an older, but consistent, filesystem state.
.It Fl y
Causes
.Nm
to assume "yes" as the answer to all questions.  In other words,
always attempt to repair any errors that are found.
.It Fl n
Causes
.Nm
to assume "no" as the answer to all questions.  In other words,
never attempt to repair any errors that are found.
.It Fl x
Causes
.Nm
to produce its output in an XML-like (plist) format.  This option is
used when another application with a graphical user interface (like
OS X Disk Utility) is invoking the
.Nm
tool and processing the output.
.It Fl g
Causes
.Nm
to produce its output in GUI-compatible form.  This is similar in
usage to the
.Fl x
option.
.It Fl l Ar logfile
Reproduce all console output, as well as additional status and
error messages, to the specified file.
.El
.Pp
Alternatively
.Ar device
can be specified as the UUID of the CoreStorage logical volume group or as
the name of a CoreStorage-hosted logical volume within that group, causing
.Nm
to derive the constituent raw device(s) from the
.Pa IORegistry .
In these cases you must indicate what object is being supplied to
identify the logical volume group:
.Bl -hang -offset indent
.It Fl -pv
the component CoreStorage physical volume(s) directly
.It Fl -uuid
the CoreStorage logical volume group (as a UUID)
.It Fl -lv
a CoreStorage logical volume (as a device name)
.El
.Sh DIAGNOSTICS
The
.Nm
utility exits with 0 if no corruption was detected or if all
corruptions were repaired, and with >0 if any unrepaired corruption
remains.
.Sh BUGS
.Nm
does not perform an exhaustive validation, nor is it able to fix
many of the inconsistencies that it does detect.
.Sh HISTORY
The
.Nm
utility first appeared along with CoreStorage in OS X 10.7.0.