Ron Johnson wrote:
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On 05/11/07 07:32, Geoffrey wrote:
John Gateley wrote:
Sorry if this is a FAQ, I did search and couldn't find much.
I need to make my Postgresql installation fault tolerant.
I was imagining a RAIDed disk array that is accessible from two
(or multiple) computers, with a postmaster running on each computer.
(Hardware upgrades could then be done to each computer at different
times without losing access to the database).
We are doing this, more or less. We use the RH cluster suite on two
machines that share a common data silo. Basically, if one machine
fails, the other fires up a postmaster and picks up where the other left
off.
That's real simple description because we actually have an active/active
configuration with multiple postmasters running on each machine. Machine
A is the active machine for databases 1-3 and machine B is the active
machine for databases 4-6. If machine A fails, postmasters are fired
up on machine B to attend to databases 1-3.
That's still not a cluster in the traditional sense.
On a cluster-aware OS and RDBMS (like Rdb/VMS and Oracle RAC, which
imperfectly got it's technology from VMS), all the databases would
be open on both nodes and they would share locking over a (usually
dedicated, and used-to-be-proprietary) network link.
Regardless of what you want to call it, it certainly seems to reflect a
solution the user might consider. I don't believe I called it a
cluster. I stated we were using software called the 'cluster suite.'
--
Until later, Geoffrey
Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
- Benjamin Franklin
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