Re: [Pgcluster-general] PostgreSQL Documentation of High - Mailing list pgsql-docs
From | Bruce Momjian |
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Subject | Re: [Pgcluster-general] PostgreSQL Documentation of High |
Date | |
Msg-id | 200611202216.kAKMGBx16139@momjian.us Whole thread Raw |
In response to | Re: [Pgcluster-general] PostgreSQL Documentation of High Availability (Markus Schiltknecht <markus@bluegap.ch>) |
Responses |
Re: [Pgcluster-general] PostgreSQL Documentation of High Availability
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List | pgsql-docs |
Markus Schiltknecht wrote: > Hi, > > a.mitani@sra-europe.com wrote: > > Current generation of PGCluster is a Shared-Nothing type of multi-master > > and syncronous replication system. > > Thank you for pointing us to yet another very common distinction in the > clustering world: shared-nothing vs. shared-disk or even > shared-everything. We don't touch that in the current documentation. Do > we want or need to do so? I feel the shared-* issue splits us up like master/slave and multi-master splits up --- it added more confusion than clarity, because many solutions fell in the middle. > > I think that the feature of this type of replication system is as the > > 'Multi-Master Replication Using Clustering' chapter of your document. > > Most probably, yes. Please note that it's not *my* document :-) Bruce > Momjian wrote most of it, with only some hints and annoying nit-picking > from my side. > > > However, Oracle RAC is a Shared-Everything type of multi-master clustering > > system. If it set up appropriately, most of these limitations would be > > improved. > > Shared-Everything, really? I thought they did their own distributed > shared memory or distributed locking stuff, so it would be shared-disk. > And together with their OCFS, they would reach shared-nothing. But I > don't really know. Yea, gets confusing. > @pgsql-docs: I'd strongly vote for not mentioning Oracle if we don't > event want to mention proprietary products for PostgreSQL. There are > enough research or ongoing projects (even some ongoing reserch projects > ;-) ) to mention. PgCluster-II, GORDA, Slony-II or Postgres-R come to mind. Good point. I mentioned Oracle RAC only because it seems to be an industry standard, so by mentioning it, people know exactly what we are talking about. Is there a better way? And people do ask for Oracle RAC, so in a way we are telling them we don't have something similar. As sad as that is, it is true currently. > > Next generation of PGCluster (I named PGCluster-II) will be a > > Shared-Everything type of multi-master clustering system as demonstrated > > in Toronto. > > Yeah, I remember that demonstration. Do you think PGCluster-II fits > what's described under 'Multi-Master Replication Using Clustering'? Do > you think we should explain Shared-Nothing vs. Shared-Disk vs. > Shared-Everything there? pgcluster is must closer to Oracle RAC, but I haven't mentioned it because I am unsure where it is in terms of usability and stability. Comments? -- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
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