diff files and copyonwrite

[g <sendmailtogoran@gmail.com>]

Hi all,

I have a nbd configured with copyonwrite (COW). This is working fine. But after
shutting all clients down I expected zero diff files.

# ls -al
total 977880
drwxr-xr-x 2 nbd  nbd        4096 Jan  5 16:18 .
drwxr-xr-x 6 root root       4096 Dec 31 20:57 ..
-rw-r--r-- 1 nbd  nbd  2147483648 Jan  5 13:00 blade.img
-rw------- 1 nbd  nbd  1144090624 Jan  7 18:59 nbd-172.16.138.59-657.diff
-rw------- 1 nbd  nbd           0 Jan  1 17:04 nbd-172.16.25.219-10932.diff
-rw------- 1 nbd  nbd           0 Jan  1 20:23 nbd-172.16.25.219-10951.diff

How can this happen and how to avoid it?

Regards

Goran