zcav(1) General Commands Manual zcav(1)
zcav - program to test raw hard drive throughput.
zcav [-b block-size] [-c count] [-u uid-to-use:gid-to-use] [-g
gid-to-use] [-f] file-name
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
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.
-b the size of the blocks to read from disk (default 100M).
-c the number of times to read the entire disk.
-f the file-name for the input data. This isn't needed on well con-
figured 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
This program, it's manual page, and the Debian package were written by
Russell Coker <russellATcoker.au>.