On Fri, Aug 31, 2018 at 3:59 PM Larry McVoy <lm@mcvoy.com> wrote:

> A bunch of people stuck around and tried, they really did and I applaud
> them for it but the damage was done.  I was gone by the time ZFS came out
> so I have no idea how that passed through the formal vetting process that
> Sun had in place.  When I was there, if I had proposed a file system that
> wouldn't use the page cache, you'd have to copy from the buffer cache
> into the page cache to get mmap to work, I would have been kicked out
> of the room and probably kicked out of the kernel group.  We had spent
> SO FRIGGING MUCH TIME getting rid of the buffer cache, precisely because
> trying to maintain coherency between the page cache (mmap) and the buffer
> cache (read/write), it was clear that you wanted a unified model.
>

It's reason #1 why Netflix can't use ZFS: the double copy problem...

Warner