using a disk "mirrored" with dd
Bill Moran
wmoran at potentialtech.com
Tue Aug 3 06:37:08 PDT 2004
Matt <finitesoup at gmail.com> wrote:
> I have a machine running 4.10-RELEASE-p2 with two identical hard disks
> -- ad0 and ad2. I would like to make a complete copy of the first disk
> to the second disk nightly for quick disaster recovery.
>
> I've dd'ed the disk as follows
>
> # dd if=/dev/ad0 of=/dev/ad2
>
> and edited the disklabel of the second disk to change ad0s1 to ad2s1 as follows
>
> # disklabel -e -r ad2
>
> However, I'm still unable to mount the root partion (or any other
> partition) of the second disk to tweak /etc/fstab etc. even though
>
> # mount /dev/ad2s1a /mnt
> mount: /dev/ad2s1a: Operation not permitted
What is your securelevel? See man securelevel.
>
> What am I missing? Is there anything else I need to do beyond editing
> the disklabel to allow me to use the "mirrored" disk?
>
> Output of disklabel for the two disks follows:
>
> # disklabel ad0
> # /dev/ad0c:
> type: ESDI
> disk: ad0s1
> label:
> flags:
> bytes/sector: 512
> sectors/track: 63
> tracks/cylinder: 255
> sectors/cylinder: 16065
> cylinders: 4864
> sectors/unit: 78156162
> rpm: 3600
> interleave: 1
> trackskew: 0
> cylinderskew: 0
> headswitch: 0 # milliseconds
> track-to-track seek: 0 # milliseconds
> drivedata: 0
>
> 8 partitions:
> # size offset fstype [fsize bsize bps/cpg]
> a: 409600 0 4.2BSD 2048 16384 97 # (Cyl. 0 - 25*)
> b: 5242880 409600 swap # (Cyl. 25*- 351*)
> c: 78156162 0 unused 0 0 # (Cyl. 0 - 4864*)
> e: 4194304 5652480 4.2BSD 2048 16384 89 # (Cyl. 351*- 612*)
> f: 10485760 9846784 4.2BSD 2048 16384 89 # (Cyl. 612*- 1265*)
> g: 18874368 20332544 4.2BSD 2048 16384 89 # (Cyl. 1265*- 2440*)
>
> # disklabel ad2
> # /dev/ad2c:
> type: ESDI
> disk: ad2s1
> label:
> flags:
> bytes/sector: 512
> sectors/track: 63
> tracks/cylinder: 255
> sectors/cylinder: 16065
> cylinders: 4864
> sectors/unit: 78156162
> rpm: 3600
> interleave: 1
> trackskew: 0
> cylinderskew: 0
> headswitch: 0 # milliseconds
> track-to-track seek: 0 # milliseconds
> drivedata: 0
>
> 8 partitions:
> # size offset fstype [fsize bsize bps/cpg]
> a: 409600 0 4.2BSD 2048 16384 97 # (Cyl. 0 - 25*)
> b: 5242880 409600 swap # (Cyl. 25*- 351*)
> c: 78156162 0 unused 0 0 # (Cyl. 0 - 4864*)
> e: 4194304 5652480 4.2BSD 2048 16384 89 # (Cyl. 351*- 612*)
> f: 10485760 9846784 4.2BSD 2048 16384 89 # (Cyl. 612*- 1265*)
> g: 18874368 20332544 4.2BSD 2048 16384 89 # (Cyl. 1265*- 2440*)
>
> Thanks for any insight, and let me know if you need to see anything else.
>
> -Matt
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--
Bill Moran
Potential Technologies
http://www.potentialtech.com
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