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 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.

-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 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.

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