Hi,
Matthew wrote:
Hey all, new postgres user here. We are trying to setup/research an
HA/Replicated solution with Postrgresql between a datacenter in LA and a
d.c. in NY.
We have a private LAN link between the two D.C.'s with a max round-trip
of 150ms.
We will have a web server at each d.c. (among other servers) that will
write/read to/from the local LAN DB. On writes, that data should be
xmited to the other data center so that if, for whatever reason, my
website request was sent to LA instead of NY, all my session information
etc will still exist.
This is commonly known as synchronous replication. As that involves
*at-least* one round-trip *before* committing, it's quite expensive. Can
you live with a delay of ~150ms before COMMIT confirmation?
Another issue is the reliability of your failure detectors. How does
server B know that server A is really down (and not only the link?).
Normally, that's solved with a quorum device. So that you have to have
at least three servers - preferably in different locations.
Regards
Markus
Disclaimer: I'm the developer behind Postgres-R (www.postgres-r.org),
have a look at it, it's designed to do what you are looking for.
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