[zfs-discuss] Re: [fbsd] Porting ZFS file system to FreeBSD.

[Eric Schrock]

On Tue, Aug 22, 2006 at 04:42:57PM +0200, Michael Schuster - Sun Microsystems wrote:
> Pawel Jakub Dawidek wrote:
> >On Tue, Aug 22, 2006 at 04:30:44PM +0200, Jeremie Le Hen wrote:
> >>I don't know much about ZFS, but Sun states this is a "128 bits"
> >>filesystem.  How will you handle this in regards to the FreeBSD
> >>kernel interface that is already struggling to be 64 bits
> >>compliant ?  (I'm stating this based on this URL [1], but maybe
> >>it's not fully up-to-date.)
> >
> >128 bits is not my goal, but I do want all the other goodies:)
> 
> are you going to attempt on-disk compatibility?

Please note that the '128-bitness' of ZFS currently only comes into play
in the on-disk format, and the allowed size of the storage pool.  This
should be very easy to maintain compatability with.  However, each
filesystem is currently limited to 64-bits, due largely to the lack of
128-bit support in the POSIX interfaces.  So there's very little 128-bit
code floating around except at the SPA layer, and as long as you have an
unsigned 64-bit type there shouldn't be any problems at higher layers.

- Eric

--
Eric Schrock, Solaris Kernel Development       http://blogs.sun.com/eschrock