PostgreSQL High Availability from the PostgreSQL Company, Command Prompt, Inc.

PostgreSQL is widely accepted as the most scalable and stable Open Source database
in the industry. It is also known to hold its own against any of the proprietary
databases as well. There are a plethora of High Availability options available
for every workload and business requirement. If you need a more customized
solution than what is below, do not hesitate to contact us.

Log Shipping:

Also known as streaming replication and Point in Time Recovery, log shipping is
a great mechanism for creating a Highly Available requirement. Log shipping is
the least administrative overhead solution for a number of business requirements
including:

DDL Replication
Zero load backups
Failover
Geographically disparate servers
You have an existing application that can not be modified
No read-only slave requirement

Solutions include: PITRTools, Walmgr

Review our Warm Standby service

Async Replication:

Asynchronous Replication provides a Master->Slave (also known as Origin->Subscriber)
model of replication. Asynchronous Replication for PostgreSQL is an excellent
option if your business requirements include:

Few DDL changes (or Managed DDL changes)
Read from Slaves
Geographically disparate servers
Failover or Switchover capability
Zero load backups

Solutions include: Replicator, Londiste, Slony

Block Replication:

Block level replication can be Synchronous or Asynchronous. It provides the
lowest level of replication between two (or more) systems. In short it replicates
disk blocks as they are modified, over the network the the receiving system. This
type of replication is particularly useful for a true HA zero data loss scenario.
Consider this option if your business requirements include:

Zero data loss
You do not need to read from the slave
You do not want to offload backups
Your slave/standby is in the same data center (synchronous)

Solutions include: DRBD (CMD only supports Linux for this option)

Review our Cold Standby : DRBD service

Also note that any of the solutions may be used in conjunction with another solution. Thus you may use Block replication, but also have log shipping for a warm standby.

If you have further questions, please contact us.