Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Happy to help. And ya, the cluster folks were just as helpful when I was starting out. It's a pretty awesome group. :) digimer On 08/20/2012 03:57 AM, Bruce Wolfe, M.S.W., CIO wrote: > TOTALLY!!! Woo-Hoo! You're the best, Digimer. I appreciate (all of) > your constant patience with us newbies. This is one of the few open > source communities that is truly inviting and accepting to help promote > the use of excellent product and support. > > Kudos to all!! > > > Bruce M. Wolfe, M.S.W., CIO > > > 24 Belvedere St. > San Rafael, CA 94901 > 415/456.5692 (Main Office) > 415/257.2493 (Direct) > 415/456.0491 (Fax) > KI6BSL (HAM) > > > "Most of the change we think we see in life is due to truths being in > and out of favor." - Robert Frost > ------------------------------------------------------------------------ > > On 08/16/2012 07:38 PM, Bruce Wolfe, M.S.W., CIO wrote: > > Thanks, Digimer, and greetings again. > > > > The configuration is: > > Failover of primary to secondary. > > Two nodes: one primary, one secondary in, as you say, a RAID 1 > > configuration. > > > > So, all three get used? In our current configuration, we are only > using > > DRBD and Heartbeat. > > To get automatic recovery after failure, yes, you need all three. > > DRBD simply replicates raw data. That's it, nothing more. Promoting a > secondary node to primary requires external actions, be it by the user > or via another program. > > Heartbeat is deprecated and has no future. Anyone using it should be > making near-term plans to get off of it. So let's take the right off the > table. > > Corosync is a stand alone tool that handles cluster membership and > message passing. It doesn't care what other programs do or how they use > it's message passing capabilities. It is merely a communications tool. > Specifically; It decided who can send and receive messages amoungst a > group of machines. In our case, we want this so that pacemaker can > coordinate actions. > > Pacemaker is a cluster resource manager. That is, it reacts to changes > in cluster membership and, based on defined policies, decides to stop, > start, migrate or otherwise act on services. It doesn't care *how* > machines in the cluster come and go, only that they do. > > So in your use case, you would setup DRBD to replicate data. Next, you > would configure corosync to say "these two nodes are members of cluster > X". Then you tell Pacemaker; "When both nodes are available, make node > 1's DRBD the primary and make node 2 secondary. However, if not 1 dies, > promote node 2 to primary. When node 1 returns, demote node 2 and > promote noed 1." > > Make sense? > > -- > Digimer > Papers and Projects: https://alteeve.com > > -- Digimer Papers and Projects: https://alteeve.ca