why /tmp increase so fast?

[fishbed]

We have about 50 processes running on AIX 5.2
this processes complied by visualage C++ 5.0
when this processor runing the /tmp filesystem increase very fast. but when we use du command check it we find very small size in /tmp filesystem ?
when killed our processes the /tmp decrease to very small size immediate.
how can I find this processos doing WHAT WITH /tmp FILESYSTEM?

 

[KenCunningham]

man fuser. fuser -u /tmp will give details of all users and their pids accessing /tmp. Then use ps and grep to examine details of the pids. However, be warned that the processes using tmp may be ephemeral and might not exist when you do your ps on them.

 

[fishbed]

I tried fuser -c /tmp
and get some PID, then I tried ps -ef | grep "PID" and find which process is using /tmp ? but how can I get more infomation? and I want to know now is why the processes are using /tmp but whit du -sk /tmp command I only find very small size? I'm sure my program not write /tmp filesystem

 

[plamb]

try lsof

 

[trifo]

It may be a program error. If your program opens a file to write, writed data in it, then removes the file from its directory, the file remains existent and takes storage place until its file handle is released.

If you delete an open file, only the I-node is deleted, thus you can not see the file in the filesystem.

--Trifo

 

[fishbed]

Thanks for everyone's help. The problem was solved.
The reason that /tmp filesystem increase so fast was that
we start our application by crontab , and in crontab command line we not specified the standard output, so the application use /tmp for it's standard output.
and we modified our crontab command line, " > /dev/null" was added on each command line and problem was solved.

 

[KenCunningham]

Good news - thanks for posting the solution.