Provided by: bonnie++_1.98build1_amd64 
NAME
zcav - program to test raw hard drive throughput.
SYNOPSIS
zcav [-b block-size[:chunk-size]] [-c count] [-r [first-block]:last-block] [-w] [-s skip-rate] [-u
uid-to-use:gid-to-use] [-g gid-to-use] [-l log-file] [-f] file-name [-l log-file [-f] file-name]...
DESCRIPTION
This manual page documents briefly the zcav, program.
Modern hard drives have a constant rotational speed but have varying numbers of sectors per track
(outside tracks are longer and have more sectors). This is referred to as Zoned Constant Angular Velocity
(or ZCAV). The outer tracks will have a higher data transfer rate due to having more sectors per track,
these tracks generally have the lower track/sector numbers.
This program tests the ZCAV performance of a hard drive, by reading the entire data on it a specified
number of times. The file name given as the first parameter, it can be specified as -, for standard
input. This file will be opened as read-only and in usual operation it will be /dev/hdX or
/dev/ide/host0/busX/targetY/lun0/disc depending on whether you use devfs or not (NB operating systems
other than Linux will have different device names).
The output should be able to be easily graphed with gnuplot which is what I use to view the results.
OPTIONS
-b the size (in Meg) of the blocks to read/write (default 512M), optionally followed by a ':' and the
chunk size for read/write operations (default 1M). Note that the chunk size must be less than or
equal to the block size and must also be significantly less than the size of the RAM in the
machine. Also note that for the write test there will be a fsync() after writing every chunk.
-c the number of times to read/write the entire disk.
-r the range of data (in Meg) to read/write on each pass (default the entire device). Useful if you
want to quickly test part of a large drive. If a single number is given then that is the last
block to read, if two numbers then it's the start and end of a range. Values are in megs, but
they are rounded down to the block size.
-s skip rate. The option -s 10 will cause it to read every 10th block and skip the rest. Accepts
values from 2 to 20.
-f the file-name for the input data. This isn't needed on well configured systems that have a recent
Glibc where you can specify the file name without the -f flag.
-u user-id to use. When running as root specify the UID to run the tests as, it is not recommended
to use root, so if you want to run as root use -u root. Also if you want to specify the group to
run as then use the user:group format. If you specify a user by name but no group then the
primary group of that user will be chosen. If you specify a user by number and no group then the
group will be nogroup.
-g group-id to use. Same as using :group for the -u parameter, just a different way to specify it
for compatibility with other programs.
-w write zero blocks to the disk instead of reading from the disk - will destroy data!
AUTHOR
This program, it's manual page, and the Debian package were written by Russell Coker
<russell@coker.com.au>.
AVAILABILITY
The source is available from http://www.coker.com.au/bonnie++ . See http://etbe.coker.com.au/category/benchmark for further information. zcav(8)