[geeks] Solaris 10 / OpenSolaris bits to be in next version of OSX

[Scott Howard]

On Thu, Aug 10, 2006 at 10:12:06AM -0400, der Mouse wrote:
> Maybe it's just me, but I'd *much* rather get a panic in that case
> rather than silently using the redundant copy.  If my system is

It doesn't silently use it, it logs the errors via FMA.  FMA could
possibly be configured to drop the disk if you really wanted to, but
for only a small number of errors I don't think this would make sense,
especially as the problem might not actually be the disk itself,
but something in between it and the host.

> You don't, actually.  If something is failing to write data, you don't
> (can't) know whether it's the data or the saved checksum that's been
> mis-written, and have no particular reason to trust the redundant copy

Sure you do, because the checksum itself was checksummed by the
metadata above it, which was checksummed by the data above it. At the top
of the tree there multiple copies (4 rings a bell?) of the data on each
disk, not to mention cross-versioning and checksumming between disks.

What I described wasn't the whole story - if you want more then
http://www.opensolaris.org/os/community/zfs/ is a good place to start.

  Scott