Alvaro Herrera <alvherre@commandprompt.com> writes:
> Tom Lane escribió:
>> It would only be useful to have one per spindle-dedicated-to-WAL, so
>> tying the division to databases doesn't seem like it'd be a good idea.
> Keep in mind that there are claims that a write-cache-enabled
> battery-backed RAID controller negates the effect of a separate spindle.
Possibly true, but if that's the underlying hardware then there's no
performance benefit in breaking WAL up at all, no?
> My point, rather, is that with this sort of setup it would be easier to
> do per-database PITR shipping, and one database's WAL activity would not
> affect another's (thus hosting providers are happier -- high-rate
> customer A need not affect low-budget customer B).
You won't get far with that because of the shared catalogs. In
particular, most DDL operations these days touch pg_shdepend ...
regards, tom lane
