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Re: Is mysql 3.2x stable enough for HA requirement?

El Thu, Apr 04, 2002 at 08:58:50AM +0800, Patrick Hsieh escribió:
> Hello Jean-Francois Dive <jef@linuxbe.org>,
> I have no problem with the robustness of PostgresSQL.
> However, does PostgreSQL have built-in replication? If not, how do I
> implement high-available PostgreSQL clusters?

 Umm, AFAIK, 7.X series of PostgreSQL have built-in support for table
replication, check de features page at their site to confirm.

 No matter if native supported or not .. there are some *load
balancing* daemons around Inet, that let you setup a group of psql
servers. Time ago I worked with one of that daemons and did this

 Node A:					Node B:				Node C:			Node D:
 psql						psql					psql				psql
 Daemon setup:			Daemon Setup:		Daemon Setup:	Daemon Setup:
	Rep. to B				Rep. to A			Rep. to A			Rep. to A
	Rep. to C				Rep. to C			Rep. to B			Rep. to B
	Rep. to D				Rep. to D			Rep. to D			Rep. to C

 It worked, but it's a big problem to have them perfecly in sync,
because if you use RR at the dns level to do another *load balancing*
task, uff, get harder to sync, beleive me.

 The best, if you target is HA and not Load Balancing is this one the
same as above, but not doing DNS RR, instead, DNS failover, if master
fails, slave get on running. Easier to keep in sync, because all the
sql statements goes from Master to Slaves, if master goes down, one of
the slaves becomes master and all contine running. In this aproach, a
*faster* solution is to do IP takeover, if master an slaves are on the
same subnet.

 Best Regards
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