Re: Replication

On 6/15/07, Craig James <craig_james(at)emolecules(dot)com> wrote:
[snip]
> Is this a good summary of the status of replication? Have I missed any important solutions or mischaracterized anything?

* Mammoth Replicator, commercial.

* Continuent uni/cluster, commercial
(http://www.continuent.com/index.php?option=com_content&task=view&id=212&Itemid=169).

* pgpool-II. Supports load-balancing and replication by implementing a
proxy that duplicates all updates to all slaves. It can partition data
by doing this, and it can semi-intelligently route queries to the
appropriate servers.

* Cybertec. This is a commercial packaging of PGCluster-II from an
Austrian company.

* Greenplum Database (formerly Bizgres MPP), commercial. Not so much a
replication solution as a way to parallelize queries, and targeted at
the data warehousing crowd. Similar to ExtenDB, but tightly integrated
with PostgreSQL.

* DRDB (http://www.drbd.org/), a device driver that replicates disk
blocks to other nodes. This works for failover only, not for scaling
reads. Easy migration of devices if combined with an NFS export.

* Skytools (https://developer.skype.com/SkypeGarage/DbProjects/SkyTools),
a collection of replication tools from the Skype people. Purports to
be simpler to use than Slony.

Lastly, and perhaps most promisingly, there's the Google Summer of
Code effort by Florian Pflug
(http://code.google.com/soc/postgres/appinfo.html?csaid=6545828A8197EBC6)
to implement true log-based replication, where PostgreSQL's
transaction logs are used to keep live slave servers up to date with a
master. In theory, such a system would be extremely simple to set up
and use, especially since it should, as far as I can see, also
transparently replicate the schema for you.

Alexander.