sync and cache

I have silly HA environment where box A and B are using the same
storage.
Box B will take over when Box A dies.

I'm guaranteed that as long as the data gets to the physical disk, data
is preserved.
(I know better, but that is not my problem). At any rate, I'm interested
in minimizing
the amount of data box A is caching as my env is relatively quiet.

My question is, is there anyway to put the backend on a 'Sync" write
through mode.
I read about -F, but that is the oposite of what I want.

Not only I want to sync, but I want to do with every write (or close to
it)

Could I use NOTIFY or triggers, or they are too high up in the food
chain....
Perhaps I need to go after the source code and recompile...
What is the default algorithm? ie when/how does PG decides to write its
buffers.

Thanks

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Medi Montaseri medi(at)CyberShell(dot)com
Unix Distributed Systems Engineer HTTP://www.CyberShell.com
CyberShell Engineering
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