Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
> Yeah, I think the question is what are the expected benefits of using
> raw devices. It might be an interesting exercise / experiment, but my
> understanding is that most of the benefits can be achieved by using file
> systems but with direct I/O and async I/O, which would allow us to
> continue reusing the existing filesystem code with much less disruption
> to our code base.
There's another very large problem with using raw devices: on pretty
much every platform, you don't get to do that without running as root.
It is not easy to express how hard a sell it would be to even consider
allowing Postgres to run as root. Between the security issues, and
the generally poor return-on-investment we'd get from reinventing
our own filesystem and I/O scheduler, I just don't see this sort of
thing ever going forward. Direct and/or async I/O seems a lot more
plausible.
regards, tom lane
