Re: Fault Tolerant Postgresql (two machines, two postmasters, one disk array)

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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.

- --
Ron Johnson, Jr.
Jefferson LA USA

Give a man a fish, and he eats for a day.
Hit him with a fish, and he goes away for good!

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