> What would the the best choice for the WAL mirroring, raid3
> or 5. How big does the WAL grow? mirroring is fine as long
> as the size isn't too big.
1. For each transaction that made some updates to DB
all log records must be available.
2. Server removes "old" (see 1.) 16Mb log files only at
checkpoint time (each ~300 sec by default).
So, in the system with low update rate/short update TX
there will be only 1 - 2 16Mb log files at any time.
Vadim