On 2008-11-02 at 09:39 -0500, Edward Ned Harvey wrote:
> Inotify etc is a really cool new(ish) technology that's not being used
> nearly as much as it could be.

Emphasis on the 'ish', since the Amiga's OS had something equivalent
(but better integrated) native back in the mid-eighties.  When I started
with Unix and asked why there was apparently nothing equivalent I was
told it was because it led to easier exploiting of race-conditions and
was bad.  I suggested fixing the race-conditions.  Silly naive me.

> So for now, there's just ZFS on Solaris and WAFL on Netapp.

FreeBSD's native snapshots in FFS seem to work equivalently to my
experience with WAFL at the underlying area but without the upper-layer
automatic mounting under .snapshot and the tricks with the hidden
directories.  I've not had cause to try them in real production use
though, as the last time I used normal filesystems like this, all
critical data was always entrusted to the NetApps.  RAID-DP and hotswap,
etc.

On 2008-11-02 at 10:55 -0600, Nathan Hruby wrote:
>   - FreeBSD has something called ggated (?)

FreeBSD has GEOM, which is a block device pluggable stack; it lets you
build software RAID of various flavours, layer in crypto, compression,
create virtual devices larger than the backing (you'd better be
monitoring and adding new backing in a timely manner), have USB sticks
transparently provide the encryption keys for other block devices, etc.
Also, partitioning of block devices can happen in GEOM, according to
several partitioning schemes, depending on which module you plug in.

One component is the GEOM Gate stuff (ggated et al) which let you export
a block device across the network, at any layer in your constructed GEOM
hierarchy.

So you could entrust the encryption to the client machine and pass I/O
requests with encrypted blocks across the network or keep the encryption
on the server and pass decrypted blocks, or layer encryption in on both
sides, or whatever.  It's all stackable.  The SAN multipath support
handled via GEOM, but AFAIK it's still limited to failover.

It certainly should be possible to construct a GEOM device which is
provided by a local disk mirrored with a remote disk via ggated.

The only bits I currently use (FreeBSD only on personal system these
days, $employer is a Linux shop) are:

 * GEOM mirror for the OS filesystems
 * GEOM BDE for encrypted swap (just append .bde to the block device
   name in /etc/fstab and the rest is handled for you in the system
   rc.d scripts)

-Phil
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