Expanding existing Hammer FS

Michael Neumann mneumann at ntecs.de
Wed Dec 17 02:46:05 PST 2008

>>> On hammer add-volume, you should specify the filesystem and the device
>>> to add, not the original device(s). And it should only operate on a
>>> live (already mounted) filesystem.
>>> hammer add-volume /myhammermount /dev/ad2
>>> hammer del-volume /myhammermount /dev/ad2
>> Hm, but what happens after a reboot? It won't boot anymore, without
>> making a change to /etc/fstab. Ideally this information would be stored
>> in the root volume (or maybe somewhere else?).
> I'd like to be able to mount by label or UUID. Currently I can do mount
> /dev/vinum/space /space, somethink like that would be nice.
But that would require some kind of registration mechanism, or
alternatively something like FreeBSD's GEOM, which detects different
kinds of filesystems and provides them as /dev/msdosfs/LABEL_OF_DISK or
/dev/ufs/LABEL. I'm not sure what is the best approach.
And it would only work for Hammer filesystems, right?

  mount_hammer -L Hammer1 /hammer1
  mount_hammer -L Hammer2 /hammer2
Where would this information be stored?

Ideally, there is a list of all available Hammer volumes stored
somewhere, like this:

Those devices can then be queried to find the ones with the label or
UUID of desire.
Ideally, Hammer volumes (and every other filesystem type) would be
autodetected. I think this is very much related to devfs registration
(both have to register somewhere).
Should there be some sort of mass-storage registration API? Btw, anyone
working on devfs?


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