Re: [SPAM] Re: Best way to replicate to large number of nodes

On 04/22/2010 10:12 AM, Ben Chobot wrote:
> On Apr 21, 2010, at 1:41 PM, Brian Peschel wrote:
>
>
>> I have a replication problem I am hoping someone has come across before and can provide a few ideas.
>>
>> I am looking at a configuration of on 'writable' node and anywhere from 10 to 300 'read-only' nodes. Almost all of these nodes will be across a WAN from the writable node (some over slow VPN links too). I am looking for a way to replicate as quickly as possible from the writable node to all the read-only nodes. I can pretty much guarantee the read-only nodes will never become master nodes. Also, the updates to the writable node are bunched and at known times (ie only updated when I want it updated, not constant updates), but when changes occur, there are a lot of them at once.
>>
> Two things you didn't address are the acceptable latency of keeping the read-only nodes in sync with the master - can they be different for a day? A minute? Do you need things to stay synchronous? Also, how big is your dataset? A simple pg_dump and some hot scp action after you batched updates might be able to solve your problem.

Latency is important. I would say 10 to 15 minutes max, but the shorter
the better. I don't have an exact size, but I believe the entire DB is
about 10 gig.

We had an idea of creating our apps write the SQL statements to a file,
rather than using an ODBC drive to directly change the DBs. Then we
could scp/rsync the files to the remote machines and execute them
there. This just seems like a very manual process though.

- Brian