On 2015-08-23 06:56, Martín Marqués wrote:
El 21/08/15 a las 20:45, Florin Andrei escribió:
The single instance scheme is not very reliable. I need to build a new
DB backend. I'll set up Postgres 9.4. Ideally, I'd like to setup 2
instances, each instance placed in a different availability zone.
Master/master replication. I'll put a load balancer (ELB) in front of
both instances.
It's not clear if the main goal is reliability (or availability), or to
balance writes.
If you are looking for HA, single master with multiple standbys is your
best bet (you can put standbys on different zones).
This is for reliability / availability.
The thing is, if I have a single master and an AZ fails, I still have to
make manual changes to switch to the healthy AZ - and, until then,
updates would fail. Master/master, in theory, should absorb single-AZ
failures without needing any manual intervention.
You can also look at BDR and have masters geographically distributed,
but I'd strongly suggest you look at the link
http://bdr-project.org/docs/stable/weak-coupled-multimaster.html, and
keep in mind that with multi-master systems you will be more prone to
data modification conflicts.
I get the sense that BDR is not 100% ready for prime time. Is that
accurate?
How about Bucardo?
https://bucardo.org/wiki/Bucardo
If I were to drop the master/master requirement and just do
master/slave, sending updates to one node, and doing all analytics on
the other node, what would be the best replication technique in this
case?
Stream replication seems the one which might fit better. Trigger based
replication would choke on large bulk loads (unless you split them up
into smaller pieces)
It's all bulk uploads for now. It's a Python script that wakes up once
in a while and dumps more data into the DB. Size varies but it can be
big.
--
Florin Andrei
http://florin.myip.org/
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