gmirror questions

Ruslan Ermilov ru at
Sun Sep 26 23:28:24 PDT 2004

Hi Pawel,

FreeBSD 5.3-BETA6 i386

I have a bunch of hopefully simple questions about gmirror(8).
My /dev/mirror/m0 is a mirror of ad1 and ad3 providers, with
the following file system layout:

	/dev/mirror/m0a /
	/dev/mirror/m0b swap
	/dev/mirror/m0f /usr
	/dev/mirror/m0e /var

Yes, I use both root and swap in GEOM_MIRROR, yay!

1.  When I try to "bsdlabel -B /dev/mirror/m0", I get:

# bsdlabel -B /dev/mirror/m0
bsdlabel: Geom not found

Hopefully, using "/dev/mirror/m0c" works.  Any clue why this
doesn't work?

2.  Before a reboot, the state of the mirror was "COMPLETE".

After a first reboot, everything was ok.  After a second
reboot, I got this:

ad0: 38166MB <ST340014A/3.06> [77545/16/63] at ata0-master UDMA100
ad1: 38204MB <SAMSUNG SV0411N/UA100-11> [77622/16/63] at ata0-slave UDMA100
ad2: 38166MB <ST340014A/3.06> [77545/16/63] at ata1-master UDMA100
ad3: 38204MB <SAMSUNG SV0411N/UA100-11> [77622/16/63] at ata1-slave UDMA100
GEOM_MIRROR: Device m0 created (id=411263865).
GEOM_MIRROR: Device m0: provider ad1 detected.
GEOM_MIRROR: Device m0: provider ad3 detected.
GEOM_MIRROR: Device m0: provider ad3 activated.
GEOM_MIRROR: Device m0: provider mirror/m0 launched.
GEOM_MIRROR: Device m0: rebuilding provider ad1.

Any idea why it thinks ad1 should be rebuilt?

3.  The syncing process takes very long, how do I tune it using
    the kern.geom.mirror sysctls?

4.  Will the following work with GEOM_MIRROR?

    - mirror m0 is originally from two 10G providers (p1 and p2)
    - remove p2 from the mirror
    - add p3 of size 20G to the mirror
    - wait until p3 synchronizes with p1
    - remove p1 from the mirror

    Will m0's size grow up to 20G after this procedure?

Ruslan Ermilov
ru at
FreeBSD committer
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