Re: Some thoughts on NFS

On Wed, Feb 20, 2019 at 7:58 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Tue, Feb 19, 2019 at 1:56 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
> > My point is that for iSCSC to be performant we'd need *all* the
> > infrastructure we also need for direct IO *and* a *lot* more. And that
> > it seems insane to invest very substantial resources into developing our
> > own iSCSI client when we don't even have DIO support. And DIO support
> > would allow us to address the error reporting issues, while also
> > drastically improving performance in a lot of situations. And we'd not
> > have to essentially develop our own filesystem etc.
>
> OK, got it. So, I'll merge the patch for direct I/O support tomorrow,
> and then the iSCSI patch can go in on Thursday. OK? :-)

Not something I paid a lot of attention to as an application
developer, but in a past life I have seen a lot of mission critical
DB2 and Oracle systems running on ext4 or XFS over (kernel) iSCSI
plugged into big monster filers, and also I think perhaps also cases
of NFS, but those systems use DIO by default (and the latter has its
own NFS client IIUC). So I suspect if you can just get DIO merged today
we can probably skip the userland iSCSI and call it done. :-P

--
Thomas Munro
https://enterprisedb.com