UNIX for Advanced & Expert Users

Dear All,
We are using COMPAQ DS -10 machines with UNIX 4.0F
System is behaving abnormal some directories shows full and they should not be . here is df -k output of a machines

Code:

 file system----1024 block-----used--available--capacity--mounted on
 /dev/rz17h-----8680793-----   1 ---    8420368---1%---- /xis_dumps

we believe that system is infected by some virus like /xis_dumps is kind of
strange.
other machine shows /usr 97% full and this should not be it

can anyone suggest a solution.. and i am beginner to UNIX.
also if anyone could suggest to make our system more secure
Thanks

The actual issue is: You are looking at the data in wrong way

Code:

file system----1024 block-----used--available--capacity--mounted on
 /dev/rz17h-----8680793-----   1 ---    8420368---1%---- /xis_dumps

This clearly says /xis_dumps is of 8680793KB in size, of which 8420368 is available, and you exhausted 1% of the total capacity of the file system. Unless you have posted the wrong data, you have nothing to worry about. Your filesystem has pretty good amount of free space.