On 06/30/2011 08:48 AM, Whit Blauvelt wrote: > On Thu, Jun 30, 2011 at 01:30:43PM +1000, Andrew Beekhof wrote: > >> I'll agree that Pacemaker isn't for everyone, I don't know about the >> one-size-fits-all comment though. > > Generally, when clothing is advertised as "one-size-fits-all," that means > "for everyone." If Pacemaker's focus is on meeting the needs of a subset of > projects rather than on fitting everyone, how is that subset defined? The > Pacemaker docs, such as they are, seem to suggest it's the solution for all. > > As they say, "To a hammer, everything looks like a nail." That is, even with > a good general-purpose tool like a hammer (or Pacemaker), a skilled > carpenter sometimes is going to reach for something else. > > Best, > Whit
If I may jump in; Clustering, as a topic or concept, is extremely wide. One can not help but use analogies or ways of speaking that, on close analysis, might not be accurate. Pacemaker, compared to alternatives like rgmanager, is very flexible and adaptable. In this regard, it fits far more scenarios than rgmanager and can be described as "one size fits all". The trick is that flexibility comes at the cost of a certain amount of complexity. To use rgmanager (which I like, by the way) to compare against, it is simple to understand. It's syntax is pretty trivial and thus is easy to learn and use. However, this results in a lot of restrictions. Imaging that you have HA virtual machines, and they can't start until storage resources have started. The VMs are configured to run on a given node, ideally, but can run on either. In rgmanager, there is no way at all to say "If the storage starts on the other node, but fails here, start my VMs over there". So then, you have a serious restriction. In pacemaker, this is possible. However, configuring such a scenario is inherently complex, by comparison. So, to summarize; Pacemaker is easy and accessible, given the complexity of the problem. It can be adapted to most any need, so it is "one size fits all". -- Digimer E-Mail: digi...@alteeve.com Freenode handle: digimer Papers and Projects: http://alteeve.com Node Assassin: http://nodeassassin.org "I feel confined, only free to expand myself within boundaries." _______________________________________________ Openais mailing list Openais@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/openais
