VDT(1) AVRB VDT(1)
Visual Disk Test Visual Disk Test
2010-10-25
NAME
vdt - visual disk test
SYNOPSIS
vdt [-options]
DESCRIPTION
vdt performs i/o tests on files, logical volumes, partitions or whole
disks.
vdt offers various disk addressing patterns and test area selections.
OPTIONS
basic parameters:
-b size alternate i/o buffer size
-c filename target file for comparison tests
-D deadline run until [[[CC]YY]MMDD]hhmm.ss
-e seed random number generator seed
-f filename use this file for read/write (compound) tests
-I 'comment' (short) information to appear on screen and logs
-m number maximum number of operations per test
-M number maximum number of passes per test
-p percent test area = given % of testsize
-P pattern filler for output buffer (0oct|Xhex|Bbin|dec|Rand|Zero)
-r filename input(source) file for read-only(comparison) tests
-s stripes split test area in given # of stripes
-t lifespan [[hh:]mm:]ss = maximum elapsed time per test
-w filename use this output file for write-only tests
-z testsize test area = just this much
-Z bulksize terminate after transfer this much
basic tests:
--make create & fill test (Bunch_of_Sectors at a time)
--poke poke test (same as '--writ --sect')
--read read test (B.o.S. at a time)
--seek seek test (same as '--read --sect')
--writ write test (B.o.S. at a time)
compound tests:
--aver ratification test (write, read back, compare)
--blot update test (read, stain, write back)
--comp comparison test (B.o.S. at a time)
--cool freshen test (read, write back)
--copy copy test (B.o.S. at a time)
--stir shuffle test (read, write somewhere else)
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VDT(1) AVRB VDT(1)
Visual Disk Test Visual Disk Test
2010-10-25
stress tests:
--boil read-only test (2 files, all addressing modes)
--brew read+write test (2 files, all addressing modes)
--burn write-only test (1 file, all addressing modes)
--cook read-only test (1 file, all addressing modes)
--mess read+write test (1 file, all addressing modes)
addressing patterns:
--incr incrementing addresses (start to end)
--decr decrementing addresses (end to start)
--conv converging addresses (edges to middle)
--scat scattering addresses (middle to edges)
--gold 'diamond'-pattern (middle to edges and back)
--spot 'X'-pattern (edges to middle and back)
--rand random addresses
region selection:
--edge --head and --tail combined
--head select initial portion of test area (default)
--core select central portion of test area
--tail select final portion of test area
--slab --edge and --core combined
--even divide test area proportionally
--flip invert selection of test area
entropy control:
--same yields same random numbers across tests
--firm yields same random numbers across platforms
--fate same as '--same --firm'
--whim extra entropy for unpredictable randomness
cache illustration:
--cloy stops after (default 90) hit limit
--glib smooth transition to next round
--snag cloggy transition to next round
operation flags:
-A append to log file
-E separate error messages into 'vdt.err'
-F force overwrite existing files
-T timestamped names for log and error files
-V show version info and exit
-v verbose and additional details
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--si use powers of 1000 not 1024
--bias skip (possibly) cached B.o.S.
--bang same as -F above
--boon allow last test to end cleanly past deadline
--daze full buffer random pattern fill (implies --stew)
--fast apply faster algorithms
--full random seek within B.o.S.
--help show this usage help
--once same as --uniq
--part compute performance using alt. buffer size
--raze flatten (truncate) output file
--sect i/o just a single (512-Byte) sector at a time
--stew applies '-P Rand' for each B.o.S.
--sync synchronous (blocking) output
--uniq test each and every random address just once
--wait request user interaction to finish
--wrap wrap around EOF until timeout
extra parameters:
-L lines override screen's # of lines
-C columns ditto for columns
USAGE
Without any options, vdt shows a minimal help message, and bails out.
Upon completion, a log file (`vdt.log' by default) can be found in the
calling directory.
The location and name of this log file can be modified by means of the
flags shown above.
Any test can be time-limited by using the '-t seconds' (or the more
complete '-t HH:MM:SS' form) option.
The '-v' flag enhances log details, changes log output format from
'line-wise' (all-in-one-line) to 'column-wise' (one info per line),
and improves visual feedback.
The -P 'fill-pattern' accepts, besides simple decimal numbers, the
forms '0<octal-number>' (eg.: 0572), 'x<hexadecimal-number>' (eg.:
Xa5b3c), 'b<binary-number>' (eg.: b01011010), the words 'zero' (for
'all-zero'), and 'random' (for a random bit pattern) -- all case-
insensitive and ranging in size from one single bit to 64 bits.
Ordinarily, Vdt does not interact with the observer, but the '--wait'
flag can give you an option to pause at test completion just before
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Visual Disk Test Visual Disk Test
2010-10-25
cleaning up the screen (specially useful if tests are short-lived).
Vdt can be interrupted at any time with '^C' (Control+C).
Command-line parameters are trimmed to no less than 512 characters per
string (larger values are 'operating system'-dependent), to avoid
buffer-overflow exploits; exceeding characters are ignored.
FILES
vdt.log vdt's log file
vdt.err separate error messages
vdt.opt vdt's options file
DIRECTORIES
$HOME/.vdt vdt's workplace (if found)
/usr/local/bin vdt's default executable path
EXAMPLES
Example 1: create and fill a 64MiB new file
$ vdt -w test.dat --make -z 64M
Example 2: basic read test from start to end
$ vdt -r test.dat --read --incr
Example 3: basic write-test an existing file from start to end
$ vdt -w test.dat --writ --incr
Example 4: stress write-test an existing file
$ vdt -w test.dat --burn
Example 5: copy-test an existing file to a new one, pausing at
completion.
$ vdt -r test.dat -w clone.dat --copy --wait
Example 6: compare-test two existing files, pausing at completion.
$ vdt -r test.dat -c clone.dat --comp --wait
Example 7: time-limited (to 3 seconds) random write-test with pause
$ vdt -w test.dat --writ --rand --wait -t 3
Example 8: same as above with synchronous/blocking output
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VDT(1) AVRB VDT(1)
Visual Disk Test Visual Disk Test
2010-10-25
$ vdt -w test.dat --writ --rand --wait -t 3 --sync
ENVIRONMENT
TERM The value of the TERM environment variable may affect
the output of `vdt'.
VDT Optionally used to automate initialization of flags
and/or parameters.
EXIT STATUS
The following exit values are returned:
0 No errors of any kind.
>0 An error occurred.
DIAGNOSTICS
EACCES Permission denied (POSIX.1)
Search permission is denied for
a component of the path prefix
of a given <pathname>.
ENOTTY Inappropriate I/O control operation (POSIX.1)
The type of the file or device being tested
is not suitable (eg. chosing a block device
instead of a raw device).
SEE ALSO
opm(1), xdf(1), iostat(1).
NOTES
Ordinarily, `vdt' does not require `root' privileges or SUID file
permissions in order to operate on regular files.
The INT, and TERM signals are caught by `vdt', allowing for an orderly
quit.
The QUIT signal causes `vdt' to restart the current test, as would
happen in the case of a window resize.
CAVEATS
On some operating systems, the logical sector size may be greater than
512 bytes.
When the test subject is big enough while available memory not so,
enlarging the screen window may avoid buffer allocation failures.
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2010-10-25
In the event of a failure to detect the actual disk/partition size,
providing an explicit test area size (by means of '-z') may circumvent
the problem.
BUGS
A screen with less than 24 lines results in garbled output.
On some systems, using the default 24x80 screen leads to a
miscalculation of available columns and a shorter block-window; the
'easier' workaround is (if possible) to manually enlarge the screen
window horizontally by at least one column, or simply to use the '-C
64' option in order to force the use of all available columns.
Not all possibly harmfull/misleading/nonsensical combinations of the
options are prevented nor handled in the appropriate manner (like, for
example, --make and --wrap), and such use possibly may (and most
certainly will) cause unpredictable results (and/or consequential
damage if the test type is not read-only).
AUTHOR
The original and current versions of `vdt' consist of code and
documentation written by:
Alexandre Botao http://botao.org
botao@unix.sh
botao@linux.sh alexandre@botao.org
COPYRIGHT
Copyright (C) 2010 Alexandre Botao
LICENSE
`vdt' is `Free and Open Source Software' (FOSS), and is licensed under
the GNU GENERAL PUBLIC LICENSE Version 3 (the "License");
You may not use `vdt' except in compliance with the License. You may
obtain a copy of the License at
http://www.gnu.org/licenses/
Additionally, a copy of the License is distributed along with `vdt' in
a file called 'LICENSE';
SUPPORT
Commercial support is NOT available for `vdt'.
Suggestions and/or bug reports are very welcome.
DISCLAIMER
`vdt' is distributed on an ``AS IS'' basis, WITHOUT ANY WARRANTY OR
CONDITIONS OF ANY KIND, either express or implied. See the License for
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VDT(1) AVRB VDT(1)
Visual Disk Test Visual Disk Test
2010-10-25
the specific language governing permissions and limitations under the
License.
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