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<body class='hmmessage'><div dir='ltr'><br>Digimer,<div> </div><div> Do you recommend any doc for Pacemaker studies? I started out few weeks ago but I would not like to simply copy and paste but create more sophisticated rules and create some OCF agents.</div><div><br></div><div> I appreciate all help you have done.<br><br><br><br><div><div id="SkyDrivePlaceholder"></div>> Date: Mon, 20 Aug 2012 09:47:24 -0400<br>> From: lists@alteeve.ca<br>> To: brucew@alcoholjustice.org<br>> CC: drbd-user@lists.linbit.com<br>> Subject: Re: [DRBD-user] Where to find review of DRBD vs Corosync<br>> <br>> Happy to help. And ya, the cluster folks were just as helpful when I was<br>> starting out. It's a pretty awesome group. :)<br>> <br>> digimer<br>> <br>> On 08/20/2012 03:57 AM, Bruce Wolfe, M.S.W., CIO wrote:<br>> > TOTALLY!!! Woo-Hoo! You're the best, Digimer. I appreciate (all of)<br>> > your constant patience with us newbies. This is one of the few open<br>> > source communities that is truly inviting and accepting to help promote<br>> > the use of excellent product and support.<br>> > <br>> > Kudos to all!!<br>> > <br>> > <br>> > Bruce M. Wolfe, M.S.W., CIO<br>> > <br>> > <br>> > 24 Belvedere St.<br>> > San Rafael, CA 94901 <br>> > 415/456.5692 (Main Office)<br>> > 415/257.2493 (Direct)<br>> > 415/456.0491 (Fax)<br>> > KI6BSL (HAM)<br>> > <br>> > <br>> > "Most of the change we think we see in life is due to truths being in<br>> > and out of favor." - Robert Frost<br>> > ------------------------------------------------------------------------<br>> > <br>> > On 08/16/2012 07:38 PM, Bruce Wolfe, M.S.W., CIO wrote:<br>> > > Thanks, Digimer, and greetings again.<br>> > ><br>> > > The configuration is:<br>> > > Failover of primary to secondary.<br>> > > Two nodes: one primary, one secondary in, as you say, a RAID 1<br>> > > configuration.<br>> > ><br>> > > So, all three get used? In our current configuration, we are only<br>> > using<br>> > > DRBD and Heartbeat.<br>> > <br>> > To get automatic recovery after failure, yes, you need all three.<br>> > <br>> > DRBD simply replicates raw data. That's it, nothing more. Promoting a<br>> > secondary node to primary requires external actions, be it by the user<br>> > or via another program.<br>> > <br>> > Heartbeat is deprecated and has no future. Anyone using it should be<br>> > making near-term plans to get off of it. So let's take the right off the<br>> > table.<br>> > <br>> > Corosync is a stand alone tool that handles cluster membership and<br>> > message passing. It doesn't care what other programs do or how they use<br>> > it's message passing capabilities. It is merely a communications tool.<br>> > Specifically; It decided who can send and receive messages amoungst a<br>> > group of machines. In our case, we want this so that pacemaker can<br>> > coordinate actions.<br>> > <br>> > Pacemaker is a cluster resource manager. That is, it reacts to changes<br>> > in cluster membership and, based on defined policies, decides to stop,<br>> > start, migrate or otherwise act on services. It doesn't care *how*<br>> > machines in the cluster come and go, only that they do.<br>> > <br>> > So in your use case, you would setup DRBD to replicate data. Next, you<br>> > would configure corosync to say "these two nodes are members of cluster<br>> > X". Then you tell Pacemaker; "When both nodes are available, make node<br>> > 1's DRBD the primary and make node 2 secondary. However, if not 1 dies,<br>> > promote node 2 to primary. When node 1 returns, demote node 2 and<br>> > promote noed 1."<br>> > <br>> > Make sense?<br>> > <br>> > -- <br>> > Digimer<br>> > Papers and Projects: https://alteeve.com<br>> > <br>> > <br>> <br>> <br>> -- <br>> Digimer<br>> Papers and Projects: https://alteeve.ca<br>> _______________________________________________<br>> drbd-user mailing list<br>> drbd-user@lists.linbit.com<br>> http://lists.linbit.com/mailman/listinfo/drbd-user<br></div></div> </div></body>
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