Upgrading from 7.2.4 (RH 8) to 7.4 (RH9)

Hi,

I would like to start planning on upgrading a few servers from RH8 to
RH9, essentially, also upgrading Postgres from 7.3.2 to 7.4 from the OS.

There's also a box with RH7.3 (postgres 7.2.1) that could be upgraded to
RH9 and Postgres 7.4.

I am not sure if I should backup (pg_dump) the databases, and do a clean
install of the OS, and do a pg_restore...OR, just upgrade the OS..?

Are there any issues that I should be aware of?

Any relevant procedure that can come handy?

Thanks,
Anjan

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