Thanks for your quick reply.
[root:node11]# gfs_tool list 4172664832 sdb cluster1:iscsi.2
[root:node12]# gfs_tool list 4172664832 sdb cluster1:iscsi.1
[root:node13]# gfs_tool list 4171632640 sdb cluster1:iscsi.0
The cookie is a local value (a memory address), I'm surprised it's the same on two of your machines.
Oh, I see! All nodes are quite the same spec. So, why does node13 have always different cookie... I stop caring about it :-)
-- Kenji