Re: the 'why' of pseudofs

[Bill Hacker <wbh@xxxxxxxxxxxxx>]

Steve O'Hara-Smith wrote:
> On Wed, 18 Feb 2009 11:10:01 +0100
> Jost Tobias Springenberg <jspringe@uos.de> wrote:
>
> > If you want to have seperate partitions instead of PFS, thats perfectly
> > fine, nobody forces you to use PFS everywhere. In fact It might be very
> > reasonable to keep data from home directories seperated from other data
> > or the like.
>
> 	It's not made immediately clear in the documentation but you can
> use a hammer filesystem as a replication master instead of a PFS. My /home
> is a hammer filesystem on it's own partition replicated to a PFS in another
> hammer filesystem on a different disc.

ACK - doing much the same (as '/home is gone, and I now live in '/wheel' 
anyway.

Here '/master' is an 'ordinary' subdir of '/', while ~/slave is the 
'usual' PFS, auto-created, per man 5 hammer and a hacked cmd_mirror.c 
compiled into a hammer binary.  This one JFDi when a new slave must be 
created on the target.

I expect that Michael will have a more elegant solution coming along 
that uses a comand-tail switch for over-ride.

> 	One thing that does trouble me a little is that the nullfs mount of
> the slave PFS is frozen while the nicely named symlink is not. The nullfs
> mount to the slave would be much more useful if it was not frozen, as it is
> I reverted the mirror-stream operation to refer to the PFS symlink and I
> don't use the nullfs mount at all for the slave PFS.

Nor I.

> 	I'm still trying to work out the logistics of doing a remote
> mirror, it seems to me that it should require root at both ends and I'm not
> entirely happy about opening up root ssh.

At the moment, I've altered the sshd configuration to permit it, and 
done exactly that. Works like a champ.

OTOH - the test boxen are isolated from the outside world.

Depending on how badly this old bod craves sleep, I should 'soon' be 
testing again with bespoke mounts on separate slices, ones that are not 
(solely) owned by root.

"IF needed* I'll create a special user with 'root-like' privs to do the 
do, but hope to not have to.

Backing up as I type in prep for a re-install, but with scp -r, not 
mirror-copy, as the restore will be to UFS, AND part of the test is how 
well *that* works 'bothway'...

'BFBI'...

Bill