iogen is an I/O generator. It forks child processes that each run a mix of reads and writes. The idea is to generate heavily fragmented files to make the hardware suffer as much as possible. This tool has been used to test filesystems, drivers, firmware, and hardware devices. It is by no means meant as a performance measuring tool since it tries to recreate the worst case scenario I/O.
Sysload SP Analyst offers powerful means to control and analyze server performance. It provides real-time, continuous, fine-grained resource monitoring across Windows, Solaris, AIX, HP/UX, Linux, I-series, Citrix, Netware, and virtual machines (VMware Vi, IBM LPARs, Solaris X, I5 OS LPARs). It also provides incident and failure risk prediction and immediate analysis of the root cause of problems, allowing you to pinpoint the application(s) or user(s) responsible for server load increases.