hi
i want to know what is lvol3?
and what is the possible reason that can make the using 100%
and how can i avoid this problem in the future
thanks

A simple Google search on lvol3 would have answered most of your query.

It depends of what OS version you are talking about and architecture (server/Workstation or 800/700...) then of which volume group...
If its 100% full and giving you trouble its most certainly /dev/vg00/lvol3 which is / (Yes root filesystem) and main reason is someone wrote something that should not be there like a big core file, or a writing to a mispelled tape device...

If you still have the problem, can you post the output from this disc space enquiry:

get the o/.p of bdf..it should be root file system..if you have not mounted anything else then remove everything that is in the /tmp directory using rm -r

Please ignore the advice from "swap". It is not safe to blindly delete the contents of /tmp on a multi-user HP-UX system which is in use. If you don't have /tmp as a separate mountpoint and it is the cause of the disc space issue consider cleansing in single user mode.