[Linux-cluster] Spectator mount option

[Kevin Anderson]

On Tue, 2008-06-24 at 09:53 +0200, Marc Grimme wrote:
> Hello,
> we are currently testing the specator mount option for giving nodes readonly 
> access to a gfs filesystem.
> 
> One thing we found out is that any node having mounted the filesystem with 
> spectator mount option cannot do recovery when a node in the cluster fails. 
> That means we need at least 2 rw-nodes. It's clear when I keep in mind that 
> the node has no rw-access to the journal and therefor cannot do the journal 
> replay. But it is not mentioned anywhere.
> 
> Could you please explain the ideas and other "unnormal" behaviors coming along 
> with the spectator mount-options.
> 
> And are there any advantages from it except the "having no journal"?
> 
Marc,

Funny you should bring this up.  We were just discussing a good use case
for the spectator mode and the advantages of it.  Dave and Chrissie are
looking at putting together a document on it, maybe you can help?

Some of items we are discussing:
- Central central cluster nodes that provide quorum votes
- Spectator nodes don't have quorum counts
- DLM balancing such that all lock hosting is done on the central
cluster nodes
- No fencing required for spectator nodes

Thanks
Kevin