> On Aug 6, 2024, at 19:45, Laurenz Albe <laurenz.albe@xxxxxxxxxxx> wrote: > I am surprised by that. Would you say that most storage systems will happily give you a > garbage block if there was a hardware problem somewhere? "Most" is hard for me to judge. HDDs can have uncorrected and undetected errors, definitely. ZFS, for example, can correct those (within limits); XFS doesn't try. I have been told that SSDs can have uncorrected/undetected errors as well, but I don't know details on that. > Turning data checksums on will write WAL for hint bits, which can significantly increase > the amount of WAL written. I was curious about that, so I just did a quick experiment using pgbench, with identical databases except for checksums. They both generated the same amount of WAL within 10% or so, so I don't think the impact is huge. (And you need the hint bits for pg_rewind, which is a nice thing to have in your back pocket if required.)
