[gentoo-user] How to find out to what file(...) writes goes on a idle system...

Hi,

on different systems I see the write stats (/proc/dikstats) to
physical existing disks steadily increasing. 
Looking at the output of lsof I cannot find any file suspicous
for receiving those writes.

In the context of preserving the live of flash media by minimizing
the count of unessary writes I want to know which
application/daemon/etc is continous writing to that media and which
"""entity""" (file/pipe/fifo...) is receiving those writes...

How can I find that information?

Thank you very much in advance for any help!
Best regards,
Meino