Using TCP load-balancers for read-only connections

As a PostgreSQL newbie, I've got a question about load-balancing/high-availability which isn't covered by Chapter 25 ("High Availability, Load Balancing and Replication") of the documentation.  But first, some background.

 

Background

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I'm planning a distributed database deployment.  The deployment will run across a small number of geographically remote sites.  I'll use Slony-I for master-slave replication between all machines in the deployment.  (The write rate is extremely low and the write latency for remote sites is acceptable.)

 

There will be 2 (or perhaps more if necessary) database nodes in each site, accessed by many clients.  For read-only operations, clients will only access nodes in their local site only.  (For write operations, they obviously have to go to the master.)

 

I want read-only operations to be tolerant of the loss of a single database node in the client's site.

 

Question

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Will a standard TCP load-balancer suffice, or do I *need* to use PgPool in raw mode (or some other equivalent)?

 

 

Many thanks,

 

Andrew