There are a number of things to check :

1) Is the TSM database spread out over multiple disks ? Having the database
spread over multiple disks will result in faster read/writes to disk and
improve the performance.

2) Check the top ten processes on the server when the paging space is high :

ps -A -Fpcpu,runame,pid,tty,args | sort -n  -r | head

3) Run the following commands throughout the day to see the server stats and
disk usage :

vmstat 2 10

iostat 2 10

Rich