Date: Fri, 16 Sep 2005 17:42:16 +0700 From: Victor Sudakov <sudakov@sibptus.tomsk.ru> To: freebsd-geom@freebsd.org Subject: Re: Create a mirror on disk with valid data Message-ID: <20050916104216.GA33576@admin.sibptus.tomsk.ru> In-Reply-To: <20050916073012.GA31056@admin.sibptus.tomsk.ru> References: <20050916073012.GA31056@admin.sibptus.tomsk.ru>
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Victor Sudakov wrote:
>
> How could it then be possible to create a mirror from a disk with
> existing data, like the man page suggests? The gmirror metadata could
> then be overwritten with user data or vice versa.
Perhaps someone would like to comment on this, which I think proves my
point:
testbsd5# dd if=/dev/zero of=/dev/ad2 count=500
500+0 records in
500+0 records out
256000 bytes transferred in 1.243238 secs (205914 bytes/sec)
testbsd5# fdisk -BI ad2
******* Working on device /dev/ad2 *******
fdisk: invalid fdisk partition table found
testbsd5# fdisk -BI ad2
******* Working on device /dev/ad2 *******
testbsd5# disklabel -w /dev/ad2s1 auto
testbsd5# newfs ad2s1a
/dev/ad2s1a: 1023.7MB (2096560 sectors) block size 16384, fragment size 2048
using 6 cylinder groups of 183.77MB, 11761 blks, 23552 inodes.
super-block backups (for fsck -b #) at:
160, 376512, 752864, 1129216, 1505568, 1881920
testbsd5#
testbsd5# gmirror label gm1 ad2
testbsd5# newfs /dev/mirror/gm1s1a
newfs: wtfs: 512 bytes at sector 2096560: Unknown error: 0
testbsd5#
testbsd5# disklabel /dev/mirror/gm1s1
# /dev/mirror/gm1s1:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 2096561 16 4.2BSD 2048 16384 28552
c: 2096577 0 unused 0 0 # "raw" part, don't edit
testbsd5#
--
Victor Sudakov, VAS4-RIPE, VAS47-RIPN
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