sg_format
(1m)
名前
sg_format - format or resize a SCSI disk (perhaps change its
block size)
形式
sg_format [--cmplst=0|1] [--count=COUNT] [--dcrt] [--early]
[--fmtpinfo=FPI] [--format] [--help] [--long] [--pfu=PFU]
[--pie=PIE] [--pinfo] [--poll=PT] [--resize] [--rto_req]
[--security] [--six] [--size=SIZE] [--verbose] [--version]
[--wait] DEVICE
説明
SG3_UTILS SG_FORMAT(8)
NAME
sg_format - format or resize a SCSI disk (perhaps change its
block size)
SYNOPSIS
sg_format [--cmplst=0|1] [--count=COUNT] [--dcrt] [--early]
[--fmtpinfo=FPI] [--format] [--help] [--long] [--pfu=PFU]
[--pie=PIE] [--pinfo] [--poll=PT] [--resize] [--rto_req]
[--security] [--six] [--size=SIZE] [--verbose] [--version]
[--wait] DEVICE
DESCRIPTION
Not all SCSI direct access devices need to be formatted and
some have vendor specific formatting procedures. SCSI disks
with rotating media are probably the largest group that do
support a 'standard' format operation. They are typically
factory formatted to a block size of 512 bytes with the
largest number of blocks that the manufacturer recommends.
The manufacturer's recommendation typically leaves aside a
certain number of tracks, spread across the media, for reas-
signment of blocks to logical block addresses during the
life of the disk.
This utility can format modern SCSI disks and potentially
change their block size (if permitted) and the block count
(i.e. number of accessible blocks on the media also known as
"resizing"). Resizing a disk to less than the manufacturer's
recommended block count is sometimes called "short stroking"
(see NOTES section). Resizing the block count while not
changing the block size may not require a format operation.
The SBC-2 standard (see www.t10.org) has obsoleted the "for-
mat device" mode page. Many of the low level details found
in that mode page are now left up to the discretion of the
manufacturer.
When this utility is used without options (i.e. it is only
given a DEVICE argument) it prints out the existing block
size and block count derived from two sources. These two
sources are a block descriptor in the response to a MODE
SENSE command and the response to a READ CAPACITY command.
The reason for this double check is to detect a "format cor-
rupt" state (see NOTES section). This usage will not modify
the disk.
When this utility is used with the "--format" (or "-F")
option it will attempt to format the given DEVICE. There is
a 10 second pause during which time the user is invited
twice (5 seconds apart) to abort sg_format. This occurs just
prior the SCSI FORMAT UNIT command being issued. See the
NOTES section for more information.
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Protection information is optional and is made up of 8 addi-
tional bytes associated with each logical block. Four pro-
tection types are defined with protection type 0 being no
additional protection bytes. See the PROTECTION TYPES sec-
tion below for more information.
OPTIONS
Arguments to long options are mandatory for short options as
well. The options are arranged in alphabetical order based
on the long option name.
-C, --cmplst=0 | 1
sets the CMPLST ("complete list") bit in the FORMAT
UNIT cdb to 0 or 1. The default is 1 in which case the
existing GLIST (grown list) is ignored. If the value
is 0 then the existing GLIST is taken into account. See
the LISTS section below. In most cases this bit should
be left set; some MO disk drives need this bit cleared.
-c, --count=COUNT
where COUNT is the number of blocks to be formatted or
media to be resized to. Can be used with either --for-
mat or --resize. With --format this option need not be
given in which case it is assumed to be zero. With
--format the interpretation of COUNT is:
(COUNT > 0) : only format the first COUNT blocks and
READ
CAPACITY will report COUNT blocks after
format
(COUNT = 0) and block size unchanged : use existing
block count
(COUNT = 0) and block size changed : recommended max-
imum block
count for new
block size
(COUNT = -1) : use recommended maximum block count
(COUNT < -1) : illegal
With --resize this option must be given and COUNT has
this interpretation:
(COUNT > 0) : after resize READ CAPACITY will report
COUNT
blocks
(COUNT = 0) : after resize READ CAPACITY will report
0 blocks
(COUNT = -1) : after resize READ CAPACITY will report
its
maximum number of blocks
(COUNT < -1) : illegal
In both cases if the given COUNT exceeds the maximum
number of blocks (for the block size) then the disk
reports an error. See NOTES section below.
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-D, --dcrt
this option sets the DCRT bit in the FORMAT UNIT com-
mand's parameter list header. It will "disable certifi-
cation". Certification verifies that blocks are usable
during the format process. Using this option may speed
the format. The default action of this utility (i.e.
when this option is not given) is to clear the DCRT bit
thereby requesting "media certification". When the DCRT
bit is set, the FOV bit must also be set hence sg_for-
mat does that.
-e, --early
during a format operation, The default action of this
utility is to poll the disk every 60 seconds to deter-
mine the progress of the format operation until it is
finished. When this option is given this utility will
exit "early", that is as soon as the format operation
has commenced. Then the user can monitor the progress
of the ongoing format operation with other utilities
(e.g. sg_turs(8) or sg_requests(8)). This option and
--wait are mutually exclusive.
-f, --fmtpinfo=FPI
sets the FMTPINFO field in the FORMAT UNIT cdb to a
value between 0 and 3. The default value is 0. The
FMTPINFO field from SBC-3 revision 16 is a 2 bit field
(bits 7 and 6 of byte 1 in the cdb). Prior to that it
was a single bit field (bit 7 of byte 1 in the cdb) and
there was an accompanying bit called RTO_REQ (bit 6 of
byte 1 in the cdb). The deprecated options "--pinfo"
and "--rto-req" represent the older usage. This option
should be used in their place. See the PROTECTION TYPES
section below for more information.
-F, --format
issue a SCSI FORMAT UNIT command. This will destroy
all the data This option is required to change the
block size of a disk. The user is given a 10 second
count down to ponder the wisdom of doing this, during
which time control-C (amongst other Unix commands) can
be used to kill this process before it does any damage.
See NOTES section for implementation details and EXAM-
PLES section for typical use.
-h, --help
print out the usage information then exit.
-l, --long
the default action of this utility is to assume 32 bit
logical block addresses. With 512 byte block size this
permits more than 2 terabytes (almost 2 ** 41 bytes) on
a single disk. This option selects commands and
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SG3_UTILS SG_FORMAT(8)
parameters that allow for 64 bit logical block
addresses. Specifically this option sets the "longlba"
flag in the MODE SENSE (10) command and uses READ
CAPACITY (16) rather than READ CAPACITY (10). If this
option is not given and READ CAPACITY (10) or MODE
SELECT detects a disk the needs more than 32 bits to
represent its logical blocks then it is set internally.
This option does not set the LONGLIST bit in the FORMAT
UNIT command. The LONGLIST bit is set as required
depending other parameters (e.g. when '--pie=PIE' is
greater than zero).
-P, --pfu=PFU
sets the "Protection Field Usage" field in the parame-
ter block associated with a FORMAT UNIT command to PFU.
The default value is 0, the only other defined value
currently is 1. See the PROTECTION TYPES section below
for more information.
-q, --pie=PIE
sets the "Protection Interval Exponent" field in the
parameter block associated with a FORMAT UNIT command
to PIE. The default value is 0. This field first
appeared in SBC-3 revision 18.
-p, --pinfo
The option is deprecated, use the --fmtpinfo=FPI option
instead. If used, then it sets bit 7 of byte 1 in the
FORMAT UNIT cdb.
-x, --poll=PT
where PT is the type of poll used. If PT is 0 then a
TEST UNIT READY command is used, otherwise a REQUEST
SENSE command is used. The default is currently 0 but
this will change to 1 in the near future. See the NOTES
sections below.
-r, --resize
rather than format the disk, it can be resized. This
means changing the number of blocks on the device
reported by the READ CAPACITY command. This option
should be used with the --count=COUNT option. The con-
tents of all logical blocks on the media remain
unchanged when this option is used. This means that any
resize operation can be reversed. This option cannot be
used together with either --format or a --size=SIZE
whose argument is different to the existing block size.
-R, --rto_req
The option is deprecated, use the --fmtpinfo=FPI option
instead. If used, then it sets bit 6 of byte 1 in the
FORMAT UNIT cdb.
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SG3_UTILS SG_FORMAT(8)
-S, --security
sets the "Security Initialization" (SI) bit in the FOR-
MAT UNIT command's initialization pattern descriptor
within the parameter list. According to SBC-3 the
default initialization pattern "shall be written using
a security erasure write technique". See the NOTES sec-
tion on the SCSI SANITIZE command.
-6, --six
Use 6 byte variants of MODE SENSE and MODE SELECT. The
default action is to use the 10 byte variants. Some MO
drives need this option set when doing a format.
-s, --size=SIZE
where SIZE is the block size (i.e. number of bytes in
each block) to format the device to. The default value
is whatever is currently reported by the block descrip-
tor in a MODE SENSE command. If the block size given by
this option is different from the current value then a
MODE SELECT command is used to change it prior to the
FORMAT UNIT command being started (as recommended in
the draft standard). Many SCSI disks have 512 byte sec-
tors by default and allow up to 16 bytes extra in a
sector (i.e. 528 byte sectors). If the given size in
unacceptable with the disk, most likely an "Invalid
field in parameter list" message will appear in sense
data (requires the use of '-v' to decode sense data).
-v, --verbose
increase the level of verbosity, (i.e. debug output).
"-vvv" gives a lot more debug output.
-V, --version
print the version string and then exit.
-w, --wait
the default format action is to set the "IMMED" bit in
the FORMAT UNIT command's (short) parameter header. If
this option (i.e. --wait) is given then the "IMMED" bit
is not set. If --wait is given the FORMAT UNIT command
waits until the format operation completes before
returning its response. This can be many hours on large
disks. This utility sets a 15 hour timeout on such a
FORMAT UNIT command!
LISTS
The SBC-3 draft (revision 29) defines PLIST, CLIST, DLIST
and GLIST in section 4.13 on "Medium defects". Briefly, the
PLIST is the "primary" list of manufacturer detected
defects, the CLIST ("certification" list) contains those
detected during the format operation, the DLIST is a list of
defects that can be given to the format operation. The GLIST
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is the grown list which starts in the format process as
CLIST+DLIST and can "grow" later due to automatic realloca-
tion (see the ARRE and AWRE bits in the read-write error
recovery mode page (see sdparm(8))) and use of the SCSI
REASSIGN BLOCKS command (see sg_reassign(8)).
The CMPLST bit (controlled by the --cmplst=0|1 option)
determines whether the existing GLIST, when the format oper-
ation is invoked, is taken into account. The sg_format util-
ity sets the FOV bit to zero which causes DPRY=0, so the
PLIST is taken into account, and DCRT=0, so the CLIST is
generated and used during the format process.
The sg_format utility does not permit a user to provide a
defect list (i.e. DLIST).
PROTECTION TYPES
SBC-3 drafts have added several "protection types" to the
"protection information" introduced in the SBC-2 standard.
See the "protection information" section (section 4.21 in
draft SBC-3 rev 29). 8 bytes of protection information are
added to each logical block (a 2 byte "logical block guard"
(CRC), a 2 byte "logical block application guard", and a 4
byte "logical block reference tag"). SBC-3 defines 4 protec-
tion types (types 0 to 4) with protection type 0 meaning no
protection information is maintained.
A device that supports protection information (i.e. supports
one or more protection types of 1 or higher) sets the "PRO-
TECT" bit in its standard INQUIRY response. It also sets the
SPT field in the EXTENDED INQUIRY VPD page response to indi-
cate which protection types it supports. The current protec-
tion type of a disk can be found in the "P_TYPE" and
"PROT_EN" fields in the response of a READ CAPACITY (16)
command (e.g. with the 'sg_readcap --long' utility).
Given that a device supports a particular protection type, a
user can then then choose to format that disk with that pro-
tection type by setting the "FMTPINFO" and "Protection Field
Usage" fields in the FORMAT UNIT command. Those fields cor-
respond to the --fmtpinfo=FPI and the --pfu=PFU options in
this utility. If FPI and PFU are both 0 (their default val-
ues) then protection type 0 is chosen. If FPI is 2 and PFU
is 0 then protection type 1 is chosen. If FPI is 3 and PFU
is 0 then protection type 2 is chosen. If FPI is 3 and PFU
is 1 then protection type 3 is chosen.
ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
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SG3_UTILS SG_FORMAT(8)
+---------------+--------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------------+
|Availability | system/storage/sg3_utils |
+---------------+--------------------------+
|Stability | Uncommitted |
+---------------+--------------------------+
NOTES
The SBC-2 standard states that the REQUEST SENSE command
should be used for obtaining progress indication when the
format command is underway. However, tests on a selection
of disks shows that TEST UNIT READY commands yield progress
indications (but not REQUEST SENSE commands). So the current
version of this utility defaults to using TEST UNIT READY
commands to poll the disk to find out the progress of the
format. The --poll=PT option has been added to control this.
When the --format option is given without the --wait option
then the SCSI FORMAT UNIT command is issued with the IMMED
bit set which causes the SCSI command to return after it has
started the format operation. The --early option will cause
sg_format to exit at that point. Otherwise the DEVICE is
polled every 60 seconds with TEST UNIT READY or REQUEST
SENSE commands until it reports an "all clear" (i.e. the
format operation has completed). Normally these polling com-
mands will result in a progress indicator (expressed as a
percentage) being output to the screen. If the user gets
bored watching the progress report then sg_format process
can be terminated (e.g. with control-C) without affecting
the format operation which continues. However a target or
device reset (or a power cycle) will probably cause the
device to become "format corrupt".
When the --format and --wait options are both given then
this utility may take a long time to return. In this case
care should be taken not to send any other SCSI commands to
the disk as it may not respond leaving those commands queued
behind the active format command. This may cause a timeout
in the OS driver (in a lot shorter period than 15 hours
applicable to some format operations). This may result in
the OS resetting the disk leaving the format operation
incomplete. This may leave the disk in a "format corrupt"
state requiring another format to remedy the situation.
When the block size (i.e. the number of bytes in each block)
is changed on a disk two SCSI commands must be sent: a MODE
SELECT to change the block size followed by a FORMAT com-
mand. If the MODE SELECT command succeeds and the FORMAT
fails then the disk may be in a state that the draft stan-
dard calls "format corrupt". A block descriptor in a subse-
quent MODE SENSE will report the requested new block size
while a READ CAPACITY command will report the existing (i.e.
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SG3_UTILS SG_FORMAT(8)
different) block size. Alternatively the READ CAPACITY com-
mand may fail, reporting the device is not ready, poten-
tially requiring a format. The solution to this situation is
to do a format again (and this time the new block size does
not have to be given) or change the block size back to the
original size.
The SBC-2 standard states that the block count can be set
back to the manufacturer's maximum recommended value in a
format or resize operation. This can be done by placing an
address of 0xffffffff (or the 64 bit equivalent) in the
appropriate block descriptor field to a MODE SELECT command.
In signed (two's complement) arithmetic that value corre-
sponds to the manufacturer's maximum recommended value. To
see exactly which SCSI commands are being executed and
parameters passed add the "-vvv" option to the sg_format
command line.
Short stroking is a technique to trade off capacity for per-
formance. Rotating disk performance is usually highest on
the outer tracks (i.e. lower logical block addresses) so by
resizing or reformatting a disk to a smaller capacity, aver-
age performance will usually be increased.
Other utilities may be useful in finding information associ-
ated with formatting. These include sg_inq(8) to fetch stan-
dard INQUIRY information (e.g. the PROTECT bit) and to fetch
the EXTENDED INQUIRY VPD page (e.g. RTO and GRD_CHK bits).
The sdparm(8) utility can be used to access and potentially
change the now obsolete format mode page.
scsiformat is another utility available for formatting SCSI
disks with Linux. It dates from 1997 (most recent update)
and may be useful for disks whose firmware is of that vin-
tage.
The COUNT numeric argument may include a multiplicative suf-
fix or be given in hexadecimal. See the "NUMERIC ARGUMENTS"
section in the sg3_utils(8) man page.
The SCSI SANITIZE command was introduced in SBC-3 revision
27. It is closely related to the ATA sanitize disk feature
set and can be used to remove all existing data from a disk.
Sanitize is more likely to be implemented on modern disks
(including SSDs) than FORMAT UNIT's security initialization
feature (see the --security option) and in some cases much
faster.
EXAMPLES
These examples use Linux device names. For suitable device
names in other supported Operating Systems see the
sg3_utils(8) man page.
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SG3_UTILS SG_FORMAT(8)
In the first example below simply find out the existing
block count and size derived from two sources: a block
descriptor in a MODE SELECT command response and from the
response of a READ CAPACITY commands. No changes are made:
sg_format /dev/sdm
Now a simple format, leaving the block count and size as
they were previously. The FORMAT UNIT command is executed
in IMMED mode and the device is polled every 60 seconds to
print out a progress indication:
sg_format --format /dev/sdm
Now the same format, but waiting (passively) until the for-
mat operation is complete:
sg_format --format --wait /dev/sdm
Next is a format in which the block size is changed to 520
bytes and the block count is set to the manufacturer's maxi-
mum value (for that block size). Note, not all disks support
changing the block size:
sg_format --format --size=520 /dev/sdm
Now a resize operation so that only the first 0x10000
(65536) blocks on a disk are accessible. The remaining
blocks remain unaltered.
sg_format --resize --count=0x10000 /dev/sdm
Now resize the disk back to its normal (maximum) block
count:
sg_format --resize --count=-1 /dev/sdm
Format with type 1 protection:
sg_format --format --fmtpinfo=2 /dev/sdm
Format with type 3 protection:
sg_format --format --fmtpinfo=3 --pfu /dev/sdm
EXIT STATUS
The exit status of sg_format is 0 when it is successful.
Otherwise see the sg3_utils(8) man page. Unless the --wait
option is given, the exit status may not reflect the success
of otherwise of the format. Using sg_turs(8) and sg_read-
cap(8) after the format operation may be wise.
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SG3_UTILS SG_FORMAT(8)
AUTHORS
Written by Grant Grundler, James Bottomley and Douglas
Gilbert.
REPORTING BUGS
Report bugs to <dgilbert at interlog dot com>.
COPYRIGHT
Copyright (C) 2005-2012 Grant Grundler, James Bottomley and
Douglas Gilbert
This software is distributed under the GPL version 2. There
is NO warranty; not even for MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE.
SEE ALSO
sg_turs(8), sg_requests(8), sg_inq(8), sg_modes(8),
sg_vpd(8), sg_reassign(8), sg_readcap(8), sg3_utils(8),
sg_sanitize(8) [all in sg3_utils], sdparm(8), scsiformat
(old), hdparm(8)
This software was built from source available at
https://java.net/projects/solaris-userland. The original
community source was downloaded from
http://sg.danny.cz/sg/p/sg3_utils-1.33.tgz
Further information about this software can be found on the
open source community website at
http://sg.danny.cz/sg/sg3_utils.html.
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