[Linux-cluster] General GFS Advice?

[D Canfield]

I'm just looking for a bit of general advice about GFS... We're 
basically just looking to use it as a SAN-based replacement for NFS.  
We've got a handful of servers that need constant read/write access to 
our users' home directories (Samba PDC/BDC, web server, network terminal 
servers, etc.), and we thought GFS might be a good replacement from a 
performance and security standpoint, let alone removing the SPOF of our 
main NFS/file server.  Another place we're thinking of using it is 
underneath our mail servers, so that as we grow, SMTP deliveries (and 
virus scanning) can happen on one machine while IMAP/POP connections can 
be served through another.

Unfortunately, even at academic prices, Red Hat wants more per single 
GFS node than I'm paying for twenty AS licenses, so I've been heading 
down this road by building from the SRPMS.  I mostly have a 2-node test 
cluster built under RHEL4, but a number of things have me a little bit 
hesitant to move forward, so I'm wondering if some folks can offer some 
advice. 

For starters, is my intended use even appropriate for GFS?  It does seem 
as though I'm looking to put an awful lot of overhead (with the cluster 
management suite) onto these boxes just to eliminate a SPOF. 

Another concern is that this list seems to have a lot more questions 
posted than answers.  Are folks running into situations where 
filesystems are hopelessly corrupted or that they've been unable to 
recover from?  That's the impression I feel like I'm getting, but I 
suppose a newbie to Linux in general could get the same impression from 
reading the fedora lists out of context.    The last thing I want to do 
is put something into production and then have unexplained fencing 
occurences or filesystem errors.

Finally, Red Hat sales is laying it on pretty heavy that the reason the 
GFS pricing is so high is because it's nearly impossible to install it 
yourself.  That was particularly true before GFS landed in Fedora.  Now 
the claim is just that it's very difficult to manage without a support 
contract.  Is this just marketing, or does GFS really turn out to be a 
nightmare to maintain?

Any insights people could provide would be appreciated.

Thanks
DC