dt-usersguide.txt

Linux磁盘测试的源代码,测试磁盘的读写性能

          Users Manual for                              November 10th, 2000
          dt - Data Test Program                              Version 13.22



          4.15  Terminal Flow Control "flow=" Option.

               This option specifies the terminal flow control to use  dur-
          ing testing.

          Special Notes:
            o  The default flow control is "xon_xoff".
            o  When using XON/XOFF flow control, you must make  sure  these
               byte  codes  (Ctrl/Q = XON = '\021', Ctrl/S = XOFF = '\023),
               since the program does not filter these  out  automatically.
               Also  be  aware  of  terminal servers (e.g., LAT), or modems
               (e.g., DF296) which may eat these characters.
            o  Some serial lines do  not  support  clear-to-send  (CTS)  or
               request-to-send  (RTS)  modem signals.  For example on Alpha
               Flamingo machines, only one port (/dev/tty00) supports  full
               modem control, while the alternate console port (/dev/tty01)
               does not.   Therefore,  if  running  loopback  between  both
               ports,  you  can not use cts_rts flow control, the test will
               hang waiting for these signals to transition  (at  least,  I
               think this is the case).


              Syntax:
                  flow=type        Set flow to: none, cts_rts, or xon_xoff.


          4.16  Record Increment "incr=" Option.

               This option controls  the  bytes  incremented  when  testing
          variable length records.  After each record, this increment value
          (default 1), is added  to  the  last  record  size  (starting  at
          "min=", up to the maximum record size "max=").

          Special Notes:
            o  If variable length record testing is enabled on fixed  block
               disks  and  this  option is omitted, then "incr= defaults to
               512 bytes.


              Syntax:
                  incr=value       Set number of record bytes to increment.


          4.17  I/O Mode "iomode=" Option.

               This option controls the I/O mode used, either  copy,  test,
          or verify modes.  The copy option was added to do a byte for byte
          copy between devices, while skipping bad blocks and keeping  file
          offsets on both disks in sync.  I've used this option to (mostly)
          recover my system disk which developed bad blocks which could not
          be  re-assigned.   A  verify operation automatically occurs after



                                       Page 10






          Users Manual for                              November 10th, 2000
          dt - Data Test Program                              Version 13.22



          the copy, which is real handy for unreliable diskettes.


              Syntax:
                  iomode=mode      Set I/O mode to: {copy, test, or verify}.


          4.18  I/O Type "iotype=" Option.

               This option controls the type of I/O performed, either  ran-
          dom or sequential.  The default is to do sequential I/O.

          Special Notes:
            o  The random number  generator  used  is  chosen  by  defines:
               RAND48  to  select  srand48()/lrand48(),  RANDOM  to  select
               srandom()/random(),   and   if    neither    are    defined,
               srand()/rand()  gets  used by default.  Refer to your system
               literature or manual pages to determine which functions  are
               supported.


              Syntax:
                  iotype=type        Set I/O type to: {random or sequential}.

          The seeks are limited to the data limited specified or calculated
          from  other  options  on the dt command line.  If data limits are
          not specified, seeks are limited to the size of  existing  files,
          or to the entire media for disk devices (calculated automatically
          by  dt).   If  the  data  limits  exceed  the  capacity  of   the
          media/partition/file  under test, a premature end-of-file will be
          encountered on reads or writes, but this is treated as a  warning
          (expected), and not as an error.

          4.19  Minimum Record Size "min=" Option.

               This option controls the minimum record  size  to  start  at
          when testing variable length records.

          Special Notes:
            o  By default, dt tests using fixed  length  records  of  block
               size "bs=" bytes.
            o  This option, in conjuntion with the "max=" & "incr=" control
               variable length record sizes.
            o  If variable length record testing is enabled on fixed  block
               disks and this option is omitted, then "min= defaults to 512
               bytes.


              Syntax:
                  min=value        Set the minumum record size to transfer.




                                       Page 11






          Users Manual for                              November 10th, 2000
          dt - Data Test Program                              Version 13.22



          4.20  Maxmimum Record Size "max=" Option.

               The option controls the maximum record size during  variable
          length record testing.

          Special Notes:
            o  If the "min=" option is specified, and this option is  omit-
               ted,  then  the maximum record size is set to the block size
               "bs=".
            o  This option, in conjuntion with the "min=" & "incr=" control
               variable length record sizes.


              Syntax:
                  max=value        Set the maximum record size to transfer.


          4.21  Logical Block Address "lba=" Option.

               This option sets the starting  logical  block  address  used
          with  the  lbdata option.  When specified, the logical block data
          (enable=lbdata) option is automatically enabled.


              Syntax:
                  lba=value        Set starting block used w/lbdata option.


          Special Notes:
            o  Please do not confuse this option with the disks' real logi-
               cal  block address.  See dt's "seek=" or "position=" options
               to set the starting file position.
            o  Also note that dt doesn't know about disk partitions, so any
               position specified is relative to the start of the partition
               used.


          4.22  Logical Block Size "lbs=" Option.

               This option sets the starting logical block size  used  with
          the  lbdata  option.   When  specified,  the  logical  block data
          (enable=lbdata) option is automatically enabled.


              Syntax:
                  lbs=value        Set logical block size for lbdata option.








                                       Page 12






          Users Manual for                              November 10th, 2000
          dt - Data Test Program                              Version 13.22



          4.23  Data Limit "limit=" Option.

               This option specifies the number of data bytes  to  transfer
          during each write and/or read pass for the test.

          Special Notes:
            o  You must specify either a data limit, record limit, or files
               limit  to initiate a test, unless the device type is "disk",
               in which case dt will automatically determine the disk capa-
               city.
            o  When specifying a runtime via  the  "runtime="  option,  the
               data  limit controls how many bytes to process for each pass
               (write and/or read pass).
            o  If you specify a infinite "limit=Inf" value, each pass  will
               continue until the end of media or file is reached.


              Syntax:
                  limit=value      The number of bytes to transfer.


          4.24  Munsa (DLM) "munsa=" Option.

               This option is used on  Tru64  Cluster  systems  to  specify
          various  distributed  lock  manager (DLM) options with devices or
          files.


              Syntax:
                  munsa=string     Set munsa to: cr, cw, pr, pw, ex.

              MUNSA Lock Options:
                  cr = Concurrent Read (permits read access, cr/pr/cw by others)
                  pr = Protected Read (permits cr/pr read access to all, no write)
                  cw = Concurrent Write (permits write and cr access to resource by all)
                  pw = Protected Write (permits write access, cr by others)
                  ex = Exclusive Mode (permits read/write access, no access to others)

                      For more details, please refer to the dlm(4) reference page.

          Special Notes:
            o  MUNSA  is  an  obsolete  Tru64  Cluster  term  which   meant
               MUltiple_Node Simultaneous_Access.  The new term is DAIO for
               Direct_Access_I/O.










                                       Page 13






          Users Manual for                              November 10th, 2000
          dt - Data Test Program                              Version 13.22



          4.25  Common Open Flags "flags=" Option.


          4.26  Output Open Flags "oflags=" Option.

               These options are used to specify  various  POSIX  compliant
          open  flags,  and  system  specific  flags, to test the affect of
          these open modes.

          Special Notes:
            o  Each operating system has  different  flags,  which  can  be
               queried by reviewing the dt help text ("dt_help").


              Syntax:
                  flags=flags      Set open flags: {excl,sync,...}.
                  oflags=flags     Set output flags: {append,trunc,...}.


          4.27  On Child Error "oncerr=" Option.

               This option allows you to control the  action  taken  by  dt
          when a child process exits with an error.  By default, the action
          is continue, which allows all child processes to run  to  comple-
          tion.   If the child error action is set to abort, then dt aborts
          all child processes if any child  process  exits  with  an  error
          status.

              Syntax:
                  oncerr={abort|continue}  Set child error action.


          4.28  Terminal Parity Setting "parity=" Option.

               This option specifies the terminal  parity  setting  to  use
          during testing.

              Syntax:
                  parity=string    Set parity to: even, odd, or none.
           on QNX parity=string    Set parity to: even, odd, mark, space, or none.


          4.29  Pass Limit "passes=" Option.

               This option controls the number of  passes  to  perform  for
          each test.

          Special Notes:
            o  The default is to perform 1 pass.





                                       Page 14






          Users Manual for                              November 10th, 2000
          dt - Data Test Program                              Version 13.22



            o  When using the "of=" option, each write/read combination  is
               considered a single pass.
            o  When multiple passes are specified, a different data pattern
               is used for each pass, unless the user specified a data pat-
               tern or pattern file.  [ Please keep this in mind when using
               the  "dispose=keep" option, since using this same file for a
               subsequent dt  read  verify  pass,  will  report  comparison
               errors... I've burned myself this way. ]