Re: ccd vs LVM

[Michael van Elst <mlelstv%serpens.de@localhost>]

On Sun, Apr 07, 2019 at 11:42:30PM +0300, Dima Veselov wrote:
> I treat fault-tolerance meaning something like cases
> of losing configuration or disk renumbering which
> always happen with FC interfaces.

The ccd configuration is stored outside the disks. With
NetBSD-8 you can configure a CCD on wedges, then renumbering
isn't an issue.

LVM stores its configuration on the disk in separate
label regions. Renumbering doesn't matter, the disks
(and disk groups) are recognized by UUIDs stored in
these labels.


> Is ccd configuration is built every time from disks
> like RAIDframe and what will happen on renumbering?


> Does NetBSD support wedge-over-ccd? I use name-mounting
> even on simple disks often.

The ccd driver learned about wedges in netbsd-8.

LVM doesn't support wedges, it creates new device nodes
like /dev/volume-group/logical-volume-name.



Greetings,
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."