freebsd-dev/usr.sbin/trim/trim.8
Eugene Grosbein 2b5691ee44 Re-add new small tool trim(8) to delete contents for blocks
on devices using wear-leveling algorithms as a few weeks passed
after review and discussion of trim(8) ceased and
we still have no utility to perform the job.

Reviewed by:	hackers@
MFC after:	2 weeks
2019-01-17 18:07:59 +00:00

168 lines
4.3 KiB
Groff

.\"
.\" Copyright (c) 2019 Eugene Grosbein <eugen@FreeBSD.org>.
.\" All rights reserved.
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" $FreeBSD$
.\"
.Dd January 18, 2019
.Dt TRIM 8
.Os
.Sh NAME
.Nm trim
.Nd erase device blocks that have no needed contents
.Sh SYNOPSIS
.Nm
.Op Fl Nfqv
.Fl [ [lo] Xo
.Bk -words
.Sm off
.Ar offset
.Op Cm K | k | M | m | G | g | T | t ]
.Sm on
.Xc
.Ek
.Bk -words
.Op Fl r Ar rfile
.Ek
.Ar device ...
.Sh DESCRIPTION
The
.Nm
utility erases specified region of the device.
It is mostly relevant for storage that implement trim (like flash based,
or thinly provisioned storage).
.Sy All erased data is lost.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl N
Do not actually erase anything but show what it would do (dry run).
Implies
.Fl v .
This is the default. Overrides
.Fl f .
.It Fl f
Perform the operation. Overrides
.Fl N .
.It Fl l Xo
.Sm off
.Ar offset
.Op Cm K | k | M | m | G | g | T | t
.Sm on
.Xc
.It Fl o Xo
.Sm off
.Ar offset
.Op Cm K | k | M | m | G | g | T | t
.Sm on
.Xc
Specify the length
.Fl l
of the region to trim or its offset
.Fl o
from the beginning of the device.
.Sy The whole device is erased by default
unless one or both of these options are presented.
.Pp
The argument may be suffixed with one of
.Cm K ,
.Cm M ,
.Cm G
or
.Cm T
(either upper or lower case) to indicate a multiple of
Kilobytes, Megabytes, Gigabytes or Terabytes
respectively.
.It Fl q
Do not output anything except of possible error messages (quiet mode).
Overrides
.Fl v .
.It Fl r Ar rfile
Uses the length of given
.Ar rfile
as length of the region to erase.
.Sy The whole device is erased by default.
.It Fl v
Show offset and length of actual region being erased, in bytes.
.El
.Pp
Later options override previous ones.
.Pp
Note that actual success of the operation depends of underlying
device driver such as
.Xr ada 4 ,
.Xr da 4
and others.
Refer to corresponding manual pages for detail on possible caveats
in low level support for ATA TRIM or SCSI UNMAP commands.
.Sh EXIT STATUS
.Ex -std
If the final erase operation fails for an argument, the
.Nm
utility returns exit code 1.
It can also return one of the exit codes defined in
.Xr sysexits 3 ,
as follows:
.Bl -tag -width ".Dv EX_UNAVAILABLE"
.It Dv EX_USAGE
The specified offset or length of the region is incorrect.
.It Dv EX_OSERR
There is no enough memory to proceed.
.It Dv EX_NOINPUT
The specified
.Ar rfile
cannot be opened (perhaps, it does not exist).
.It Dv EX_IOERR
The specified
.Ar rfile
cannot be examined for its size due to some system input/output error.
.It Dv EX_DATAERR
The specified
.Ar rfile
is not regular file, directory nor special device, so its size
cannot be examined.
.It Dv EX_UNAVAILABLE
The specified
.Ar rfile
is special device file not supporting DIOCGMEDIASIZE
.Xr ioctl 2
(probably not a disk), so its size cannot be examined.
.El
.Sh SEE ALSO
.Xr ada 4 ,
.Xr da 4 ,
.Xr ioctl 2 ,
.Xr nda 4 ,
.Xr sysexits 3
.Sh HISTORY
The
.Nm
utility first appeared in
.Fx 12.1 .
.Sh AUTHORS
The
.Nm
utility was written by
.An Eugene Grosbein Aq Mt eugen@FreeBSD.org .