Ping pong
From SambaWiki
Testing a filesystem with the ping_pong tool
The ping_pong tool is a tiny piece of C code that can be used to tell you some very useful things about a cluster filesystem. If you are interested in seeing if your favourite cluster filesystem might be used for CTDB/Samba then I highly recommend starting by running ping_pong and making sure it passes.
Getting ping_pong
Download it from http://junkcode.samba.org/ftp/unpacked/junkcode/ping_pong.c
Compile it like this:
cc -o ping_pong ping_pong.c