IBM provides a tool called Comprestimator, which is a command-line utility which can be ran on a variety of hosts and is used to get an estimate of the expected compression rate for block storage devices.
The utility works on the following host types:
- Red Hat Enterprise Linux Version 5 (64-bit)
- ESXi 4.0, 5.0
- AIX V6.1, V7.1
- HP-UX 11i v3
- Windows 2003 Server, Windows 2008 Server (32-bit and 64-bit)
More information on the tool and the download location is available at the following URL: