On 4/29/15 1:13 PM, Alex Gregory wrote:
I was thinking that I could use Slony but then I read that it does not like WAN replication. I have also read about streaming replication native to Postgres but was not sure how that would work over the WAN. Bucardo seems better for Data Warehousing or multimaster situations which this is not. That leaves pgpool ii which seems like it would add an extra layer of complexity.
WAN delays can cause problems for any replication system; you just have to be aware of that and not push things too hard (or try and violate the laws of physics). For example, streaming replication set to be synchronous crossing the planet is something you'd probably be rather unhappy with. :)
I haven't played with Slony in forever, but when I did it loved to lock things. That would not play well with high latency.
I have run londiste between sites within the same city, and that worked well.
Bucardo and pg_pool are both based on the idea of replaying SQL statements instead of replicating actual data. They have their uses, but I personally distrust that idea, especially for DR.
When it comes down to to there are so many choices I am not sure if I need one or a combination of two. Any help you could provide could be greatly appreciated.
If you want to replicate within a data center then streaming replication is pretty nice, and as a bonus you might be able to do synchronous as well. The downside to streaming rep is that it's binary, so if you ever suffer data corruption you're practically guaranteed that corruption will end up on the replica. Logical replication like londiste or Slony are much more robust against that. You also can't use temporary tables with streaming rep, and you have to replicate the details of ALL activity, including maintenance like VACUUM. In some environments that might be slower than logical replication.
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