.SH SYNOPSIS
.B badblocks
[
-.B \-svwnf
+.B \-svwnfBX
]
[
.B \-b
-.I block-size
+.I block_size
]
[
.B \-c
.I blocks_at_once
]
[
+.B \-d
+.I read_delay_factor
+]
+[
+.B \-e
+.I max_bad_blocks
+]
+[
.B \-i
.I input_file
]
.B \-p
.I num_passes
]
+[
+.B \-t
+.I test_pattern
+]
.I device
[
-.I blocks-count
+.I last_block
] [
-.I start-block
+.I first_block
]
.SH DESCRIPTION
.B badblocks
.I device
is the special file corresponding to the device (e.g
.IR /dev/hdc1 ).
-.I blocks-count
-is the number of blocks on the device; if it is not specified, the size
-of the device is used as a default.
-.I start-block is an optional parameter specifying the starting block number
-for the test, which allows the testing to start in the middle of the disk.
+.I last_block
+is the last block to be checked; if it is not specified, the last block
+on the device is used as a default.
+.I first_block
+is an optional parameter specifying the starting block number
+for the test, which allows the testing to start in the middle of the
+disk. If it is not specified the first block on the disk is used as a default.
+.PP
+.B Important note:
+If the output of
+.B badblocks
+is going to be fed to the
+.B e2fsck
+or
+.B mke2fs
+programs, it is important that the block size is properly specified,
+since the block numbers which are generated are very dependent on the
+block size in use by the filesystem.
+For this reason, it is strongly recommended that
+users
+.B not
+run
+.B badblocks
+directly, but rather use the
+.B \-c
+option of the
+.B e2fsck
+and
+.B mke2fs
+programs.
.SH OPTIONS
.TP
-.BI \-b " block-size"
-Specify the size of blocks in bytes.
+.BI \-b " block_size"
+Specify the size of blocks in bytes. The default is 1024.
.TP
.BI \-c " number of blocks"
-is the number of blocks which are tested at a time. The default is 16.
-Increasing this number will increase the efficiency of
-.B badblocks
-but also will increase its memory usage.
-.B Badblocks
-needs memory proportional to the number of blocks tested at once, in
-read-only mode, proportional to twice that number in read-write mode,
-and proportional to three times that number in non-destructive read-write
-mode. If you set the number-of-blocks parameter to too high a value,
-.B badblocks
-will exit almost immediately with an out-of-memory error "while allocating
-buffers". If you set it too low, however, for a non-destructive-write-mode
-test, then it's possble for questionable blocks on an unreliable
-hard drive to be hidden by the effects of the hard disk track buffer.
+is the number of blocks which are tested at a time. The default is 64.
+.TP
+.BI \-d " read delay factor"
+This parameter, if passed and non-zero, will cause bad blocks to sleep
+between reads if there were no errors encountered in the read
+operation; the delay will be calculated as a percentage of the time it
+took for the read operation to be performed. In other words, a value of
+100 will cause each read to be delayed by the amount the previous read
+took, and a value of 200 by twice the amount.
+.TP
+.BI \-e " max bad block count"
+Specify a maximum number of bad blocks before aborting the test. The
+default is 0, meaning the test will continue until the end of the test
+range is reached.
.TP
.B \-f
Normally, badblocks will refuse to do a read/write or a non-destructive
-test on a device which is mounted, since this can cause the system to
-potentially crash. This can be overriden using the
-.B \-
-flag, but this should not be done under normal circumstances. The only time
-when this option might be safe is if the /etc/mtab file is incorrect, and
-the device really isn't mounted.
+test on a device which is mounted, since either can cause the system to
+potentially crash and/or damage the filesystem even if it is mounted
+read-only. This can be overridden using the
+.B \-f
+flag, but should almost never be used --- if you think you're smarter
+than the
+.B badblocks
+program, you almost certainly aren't. The only time when this option
+might be safe to use is if the /etc/mtab file is incorrect, and the device
+really isn't mounted.
.TP
.BI \-i " input_file"
Read a list of already existing known bad blocks.
can be used to retrieve the list of blocks currently marked bad on
an existing filesystem, in a format suitable for use with this option.
.TP
+.B \-n
+Use non-destructive read-write mode. By default only a non-destructive
+read-only test is done. This option must not be combined with the
+.B \-w
+option, as they are mutually exclusive.
+.TP
.BI \-o " output_file"
Write the list of bad blocks to the specified file. Without this option,
.B badblocks
for use by the
.
.B \-l
-option in
+option in
.BR e2fsck (8)
or
.BR mke2fs (8).
.B badblocks
will exit after the first pass.
.TP
-.B \-n
-Use non-destructive read-write mode.
-.TP
.B \-s
-Show the progress of the scan by writing out the block numbers as they
-are checked.
+Show the progress of the scan by writing out rough percentage completion
+of the current badblocks pass over the disk. Note that badblocks may do
+multiple test passes over the disk, in particular if the
+.B \-p
+or
+.B \-w
+option is requested by the user.
+.TP
+.BI \-t " test_pattern"
+Specify a test pattern to be read (and written) to disk blocks. The
+.I test_pattern
+may either be a numeric value between 0 and ULONG_MAX-1 inclusive, or the word
+"random", which specifies that the block should be filled with a random
+bit pattern.
+For read/write (\fB-w\fR) and non-destructive (\fB-n\fR) modes,
+one or more test patterns may be specified by specifying the
+.B -t
+option for each test pattern desired. For
+read-only mode only a single pattern may be specified and it may not be
+"random". Read-only testing with a pattern assumes that the
+specified pattern has previously been written to the disk - if not, large
+numbers of blocks will fail verification.
+If multiple patterns
+are specified then all blocks will be tested with one pattern
+before proceeding to the next pattern.
.TP
.B \-v
-Verbose mode.
+Verbose mode. Will write the number of read errors, write errors and data-
+corruptions to stderr.
.TP
.B \-w
Use write-mode test. With this option,
.B badblocks
scans for bad blocks by writing some patterns (0xaa, 0x55, 0xff, 0x00) on
every block of the device, reading every block and comparing the contents.
+This option may not be combined with the
+.B \-n
+option, as they are mutually exclusive.
+.TP
+.B \-B
+Use buffered I/O and do not use Direct I/O, even if it is available.
+.TP
+.B \-X
+Internal flag only to be used by
+.BR e2fsck (8)
+and
+.BR mke2fs (8).
+It bypasses the exclusive mode in-use device safety check.
.SH WARNING
Never use the
.B \-w
-option on an device containing an existing file system.
+option on a device containing an existing file system.
This option erases data! If you want to do write-mode testing on
an existing file system, use the
.B \-n
-option. It is slower, but it will preserve your data.
+option instead. It is slower, but it will preserve your data.
+.PP
+The
+.B \-e
+option will cause badblocks to output a possibly incomplete list of
+bad blocks. Therefore it is recommended to use it only when one wants
+to know if there are any bad blocks at all on the device, and not when
+the list of bad blocks is wanted.
.SH AUTHOR
.B badblocks
was written by Remy Card <Remy.Card@linux.org>. Current maintainer is
implemented by David Beattie <dbeattie@softhome.net>.
.SH AVAILABILITY
.B badblocks
-is part of the e2fsprogs package and is available for anonymous
-ftp from tsx-11.mit.edu in /pub/linux/packages/ext2fs.
+is part of the e2fsprogs package and is available from
+http://e2fsprogs.sourceforge.net.
.SH SEE ALSO
.BR e2fsck (8),
.BR mke2fs (8)
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff