On Thu, Jan 12, 2012 at 5:08 AM, David Teigland <teigland@xxxxxxxxxx> wrote: > On Wed, Jan 11, 2012 at 11:21:59AM -0500, David Teigland wrote: >> > I much prefer the expected_votes field to any enumeration of the nodes. >> >> Expect admins to keep track of what expected_votes should be? >> That sounds nearly impossible to do correctly. >> >> > Does anyone need the list of nodes to be preconfigured? >> >> The alternative would be trying to remember what they all are? >> Defining the set of nodes that compose the cluster seems like >> a very good thing just for its own sake. > > I guess that's just one view. There really are two legitimate styles > of assembling a cluster that we're trying to merge. > > In the first, you have a conceptual view of just a big pool nodes, more > or less anonymous. They are just "workers", which higher level software > (e.g. pacemaker) can use as needed to run things. > > The second is a more fixed, static approach. You start with with some > specific nodes and you want to access some shared resource from those > nodes. Because the resource is shared, there needs to be clustering > involved to access it. e.g. this node needs to mount that gfs2 file > system. > > The first view has historically been taken by corosync and pacemaker, > and the second by cman/gfs2. Folks with the first view would think > of a static node list as unnecessary, whereas it's the starting point > in the second view. Surely a gfs2 partition can be mounted from nodes that were unknown when it was formatted? I don't know about cman being in the "static list" either since it also allowed nodes to be dynamically added at runtime. So I think its an artificial distinction, everyone needs a list of its peers. Where we seem to disagree is how that list is constructed. You want it configured manually, and I think we should automate it. We already have the details, we all make the necessary adjustments when a new peer appears, why force the user to write it down too? > Anyway, I think that explains the disconnect. Getting back to the real > question of what needs a node list, quorum is the only thing I can think of. Fabio says quorum doesn't need it, that expected_votes is enough. _______________________________________________ discuss mailing list discuss@xxxxxxxxxxxx http://lists.corosync.org/mailman/listinfo/discuss
