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.TH SG_REM_REST_ELEM "8" "June 2022" "sg3_utils\-1.48" SG3_UTILS
.SH NAME
sg_rem_rest_elem \- send SCSI remove or restore element command
.SH SYNOPSIS
.B sg_rem_rest_elem
[\fI\-\-capacity=RC\fR] [\fI\-\-element=EID\fR] [\fI\-\-help\fR]
[\fI\-\-quick\fR] [\fI\-\-remove\fR] [\fI\-\-restore\fR] [\fI\-\-verbose\fR]
[\fI\-\-version\fR] \fIDEVICE\fR
.SH DESCRIPTION
.\" Add any additional description here
.PP
Sends a SCSI REMOVE ELEMENT AND TRUNCATE [RMEAT] or RESTORE ELEMENTS AND
REBUILD [RSEAR] command to the \fIDEVICE\fR. Since both these commands have
a potentially huge impact on the \fIDEVICE\fR (similar to the FORMAT UNIT
command: destroying data and taking a long time to complete fully),
they first give the user the chance to reconsider (3 times within 15
seconds) before taking action.
.PP
Unlike the FORMAT UNIT command, these commands seem designed to work in
the background. So they will return quickly (although sbc5r01.pdf does not
state that) and the disk will be placed in a reduced functionality state
where only a specified number of commands will be executed (e.g. INQUIRY and
REPORT LUNS) until the operation is complete. Other commands will receive
sense data with a sense key of NOT READY and an additional sense code
of 'Depopulation in progress' (for RMEAT) or 'Depopulation restoration in
progress' (for RSEAR).
.PP
The REMOVE ELEMENT AND TRUNCATE has a close relative in ZBC\-2 called the
REMOVE ELEMENT AND MODIFY ZONES [RMEMZ] command. See the sg_zone utility
for an implementation of the latter command.
.br
The difference between RMEAT and RMEMZ is that the former "changes the
association between LBAs and physical blocks" and the latter does not
change that association. Zones affected by the RMEMZ command are placed
into the zone condition: "Offline".
.SH OPTIONS
Arguments to long options are mandatory for short options as well.
.TP
\fB\-c\fR, \fB\-\-capacity\fR=\fIRC\fR
RC stands for Requested Capacity and is the number of logical blocks the
\fIDEVICE\fR should have after the element is removed with the RMEAT
command. The default value is 0 which allows the \fIDEVICE\fR to decide
what the reduced capacity will be after the element removal. The RSEAR
command ignores this value.
.TP
\fB\-e\fR, \fB\-\-element\fR=\fIEID\fR
where \fIEID\fR is an element identifier which is a 32 bit unsigned integer
starting at one. This field is used by the RMEAT command and ignored
otherwise. The default value is zero (which is invalid). So the user needs
to supply a valid element identifier when \fI\-\-remove\fR is used.
.TP
\fB\-h\fR, \fB\-\-help\fR
output the usage message then exit.
.TP
\fB\-q\fR, \fB\-\-quick\fR
the default action (i.e. when this option is not given) is to give the user
15 seconds to reconsider doing a remove or restore element operation on the
\fIDEVICE\fR. When this option is given that step (i.e. the 15 second
warning period) is bypassed.
.TP
\fB\-r\fR, \fB\-\-remove\fR
causes the REMOVE ELEMENT AND TRUNCATE command to be sent to the
\fIDEVICE\fR. In practice, \fI\-\-element=EID\fR needs to be also given.
.TP
\fB\-R\fR, \fB\-\-restore\fR
causes the RESTORE ELEMENTS AND REBUILD command to be sent to the
\fIDEVICE\fR.
.TP
\fB\-v\fR, \fB\-\-verbose\fR
increase the level of verbosity, (i.e. debug output).
.TP
\fB\-V\fR, \fB\-\-version\fR
print the version string and then exit.
.SH NOTES
Once an element is removed successfully it is termed as "depopulated".
Depopulated elements that have the 'Restoration Allowed' (RALWD) bit
set (see sg_get_elem_status) are candidates for future restoration.
.PP
A (storage) element of a rotating hard disk is one side of a platter
typically associated with one head. Such hard disks typically have multiple
platters with two heads per platter (i.e. one head each side of the platter).
.SH EXIT STATUS
The exit status of sg_rem_rest_elem is 0 when it is successful. Otherwise see
the sg3_utils(8) man page.
.SH AUTHORS
Written by Douglas Gilbert.
.SH "REPORTING BUGS"
Report bugs to <dgilbert at interlog dot com>.
.SH COPYRIGHT
Copyright \(co 2022 Douglas Gilbert
.br
This software is distributed under a BSD\-2\-Clause license. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
.SH "SEE ALSO"
.B sg_get_elem_status,sg_zone(sg3_utils)
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