Does it have to be graphical ? I have found that the regular top utility is better than the all the graphical utilities I have tried, especially for a dual CPU system. I don't think that top has any info for disk usage however.
On my main Unix server, I use a command called iostat for monintoring disk activity. The command iostat dsk2 dsk3 dsk4 5 5 produces 5 iterations (one every 5 seconds) for the 3 devices (dsk2 dsk3 dsk4). If you try iostat 5 1000 > diskio.txt, you will have 1000 iterations written to the textfile of your choice. Below is a sample output - bps is bytes per second throughput (kbytes/sec on this server), tps is transfers per second. The server below has an enormous amount of ram, so the disk activity is very slight.
iostat dsk2 dsk3 dsk4 5 5
tty dsk2 dsk4 dsk3 cpu
tin tout bps tps bps tps bps tps us ni sy id
29 324 256 4 359 9 325 6 2 0 1 97
29 71 0 0 2 0 0 0 50 0 0 50
31 475 0 0 0 0 0 0 51 0 0 48
27 1256 2 0 16 2 0 0 51 0 1 48
37 753 3 0 34 2 0 0 50 0 1 49
My Linux server does not include iostat, but here is a link where you can read about it and download it:
http://www.icewalkers.com/Linux/Softwar ... sstat.html
It also talks about a utility called sar. I used sar when I was working at a different company several years ago, and I found it better overall than iostat and vmstat. You may want to check it out. If you need to do any serious performance tuning, you will eventually want something that writes to a file - you can have it run all day if you want, and and analyze it quickly when it finishes.
EDIT: The columns from the sample output (iostat) line up much better for real then what I pasted.
