1zcav(8)                     System Manager's Manual                    zcav(8)
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NAME

6       zcav - program to test raw hard drive throughput.
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SYNOPSIS

10       zcav      [-b      block-size[:chunk-size]]      [-c     count]     [-r
11       [first-block]:last-block]      [-w]      [-s       skip-rate]       [-u
12       uid-to-use:gid-to-use] [-g gid-to-use] [-l log-file] [-f] file-name [-l
13       log-file [-f] file-name]...
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DESCRIPTION

17       This manual page documents briefly the zcav, program.
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19       Modern hard drives have a constant rotational speed  but  have  varying
20       numbers  of  sectors per track (outside tracks are longer and have more
21       sectors). This is referred to as Zoned Constant  Angular  Velocity  (or
22       ZCAV).  The  outer  tracks will have a higher data transfer rate due to
23       having more sectors per track, these tracks generally  have  the  lower
24       track/sector numbers.
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26       This program tests the ZCAV performance of a hard drive, by reading the
27       entire data on it a specified number of times. The file name  given  as
28       the first parameter, it can be specified as -, for standard input. This
29       file will be opened as read-only and in  usual  operation  it  will  be
30       /dev/hdX  or /dev/ide/host0/busX/targetY/lun0/disc depending on whether
31       you use devfs or not (NB operating systems other than Linux  will  have
32       different device names).
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34       The  output  should  be able to be easily graphed with gnuplot which is
35       what I use to view the results.
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OPTIONS

39       -b     the size (in Meg) of the blocks to  read/write  (default  512M),
40              optionally  followed  by a ':' and the chunk size for read/write
41              operations (default 1M).  Note that the chunk size must be  less
42              than  or  equal to the block size and must also be significantly
43              less than the size of the RAM in the machine.   Also  note  that
44              for  the  write test there will be a fsync() after writing every
45              chunk.
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48       -c     the number of times to read/write the entire disk.
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51       -r     the range of data (in Meg) to read/write on each  pass  (default
52              the  entire device).  Useful if you want to quickly test part of
53              a large drive.  If a single number is given  then  that  is  the
54              last  block  to read, if two numbers then it's the start and end
55              of a range.  Values are in megs, but they are  rounded  down  to
56              the block size.
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59       -s     skip  rate.   The  option -s 10 will cause it to read every 10th
60              block and skip the rest.  Accepts values from 2 to 20.
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63       -f     the file-name for the input data. This isn't needed on well con‐
64              figured  systems  that have a recent Glibc where you can specify
65              the file name without the -f flag.
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68       -u     user-id to use.  When running as root specify the UID to run the
69              tests  as,  it is not recommended to use root, so if you want to
70              run as root use -u root.  Also if you want to specify the  group
71              to run as then use the user:group format.  If you specify a user
72              by name but no group then the primary group of that user will be
73              chosen.   If  you specify a user by number and no group then the
74              group will be nogroup.
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77       -g     group-id to use.  Same as using :group  for  the  -u  parameter,
78              just  a different way to specify it for compatibility with other
79              programs.
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82       -w     write zero blocks to the disk instead of reading from the disk -
83              will destroy data!
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AUTHOR

87       This  program, it's manual page, and the Debian package were written by
88       Russell Coker <russell@coker.com.au>.
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AVAILABILITY

92       The source is available from http://www.coker.com.au/bonnie++ .
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94       See http://etbe.coker.com.au/category/benchmark  for  further  informa‐
95       tion.
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