[Samba] Cluster Locking

[Matt Perkins]

I have been running a Samba cluster in active/passive mode using Linux
HA (http://www.linux-ha.org) for several years. With the release of the
GFS filesystem, I was hoping to begin running the servers as an
active/active pair with transparent failover. In my test environment, I
have two computers running Fedora Core 4 attached directly to a SCSI
disk array formatted with GFS. I have
symlinked /etc/samba, /var/log/samba and /var/cache/samba to the GFS
filesystem. According to the post by Gerald (Jerry) Carter at
http://groups-beta.google.com/group/linux.samba/browse_frm/thread/e6aa38dcce2ce5e3/ca0a5ce2496059c4?lnk=st&q=%22can+we+export+cluster+file+system%22&rnum=1#ca0a5ce2496059c4 , this is the way to get two clustered systems to share locking information. However, when I connect to one of the servers and open a file, the other server is not aware that the file is open.

According to
http://us3.samba.org/samba/docs/man/Samba-HOWTO-Collection/SambaHA.html#id2652330 in the Conclusions section, "Transparent SMB clustering is hard to do" and "Client failover is the best we can do right now".

Andrew Tridgell's Ping Pong tool at http://junkcode.samba.org/#ping_pong
demonstrates "the futility of trying to do a high performance
distributed SMB server".

Here are my questions: Have I missed something in my test environment?
Should I be able to use shared .tdbs to keep track of open files among
clustered servers? Is an active/active cluster possible?

Thanks!
Matt Perkins RHCE, MCSE