Ludek, AFAICT a cluster of multiple quad CPU machines is huge, massive
overkill for all but a minuscule fraction of RDBMS backed websites,
even if you are also integrating substantial amounts of data
that is not directly web-related. (One modern dual CPU box with 16 or
32 GB of RAM can do a
lot...) So you aren't likely to find
all that much real interest in such RDBMS clustering in the OpenACS
community.
Do you seriously anticipate a need for such clustering at AIESEC, or
are you just asking for background knowledge? What does your current
RDBMS dataset, usage, hardware, and load look like?
I have not tried out Oracle 10g's clustering features at all yet. I
will sometime, but for its remote offsite backup and failover
capabilities, not in an attempt to increase performance. My (limited)
understanding is that this is what all of Oracle's
"clustering" functionality is primarily aimed at - data integrity and
business continuity, not increased throughput. In fact I believe
using Oracle clustering tends to slow down your RDBMS slightly vs. the
single box case, not speed it up. (You may, of course, get a speed up
if you use the slave nodes for large slow read-only queries, thus
unloading those from the master node.)
PostgreSQL does have extensive replication and failover capabilities
now, but I'm not particularly familiar with them, nor how they compare
to what Oracle 10g has. That said, I think PostgreSQL does not yet
have multi-master (writes allowed on multiple nodes) capability
(Oracle does), but they're working on it.
For some related links see these older threads:
one,
two,
three.
