How do I gmirror slices?

[R. B. Riddick]

before u go on further, I would like to advise u to do a backup ur data...

u should try to understand first, what the commands do (try "man cpio" for
example)... Then u should do some exercises in a sub directory (like
/tmp/blubber) until u feel like u understood it sufficiently...

--- Hansa <mythtv at logic-q.nl> wrote:
> > > # /dev/ad4s1:
> > > 8 partitions:
> > > #        size   offset    fstype   [fsize bsize bps/cpg]
> > >   a:  4192256        0    4.2BSD        0     0     0
> > >   b:  4192256  4192256      swap
> > >   c: 12578832        0    unused        0     0         # "raw" part,
> don't edit
> > >   d:  4194320  8384512    4.2BSD        0     0     0
> > >
> > Here we see, that d ends on the last sector of slice 1 (s1).
> > So u need to shrink partition d by one sector.
> > Since UFS might use that sector, u need an all new file system
> > for partition
> > d...
> How do you determine that it's on the last sector?
>
4194320+8384512 = 12578832 ==> d ends on the last sector

> > Maybe u want to it like this:
> > 1. fdisk ur new disk first
> Should I create the the new disk (ad6) slice size exactly as on ad4?
>
I dont know... If u want to change the file system sizes: Now is the right
moment... But if u change it, u have to change it on ad4, too...

> Hmm.. I'm already stuck at 1. Since I've never done this before, can you
> help me on my way by specifying the correct commands? Here's what I've come
> up with so far:
> 1. Using fdisk in /stand/sysinstall presuming same slice size as ad4.
>
OK

> 2. # gmirror label -v -b round-robin gm0 /dev/ad6s1
>    # gmirror label -v -b round-robin gm0 /dev/ad6s2
>
looks good

> 3. # dd if=/dev/ad4s3d of=/mnt/netwshare/ad4s3d.backup
>
looks not good, because:
(aa) dd uses a default block size of 512 bytes, so that it does many
requests... Better would be bs=1m or so...
(bb) u should use "cd /oldhome ; find . | cpio -o >
/mnt/netwshare/old-home.cpio" and later "cd /newhome ; cpio -i
--preserve-modification-time . < /mnt/netwshare/old-home.cpio"

> 4. Have not dug into that yet.
>
OK - can wait...

> 5. I guess you mean copying ad4s1a, ad4s1b, ad4s1d and ad4s2d to te
> gmirror-ed. Can I use dd for that?
>
first u should go to single user mode and mount those old file systems
read-only:
(aa) single-user (CAVE: 100% service interruption): "kill 1"
(bb) mount -r /
(cc) mount -r /dev/ad4s1d
(dd) mount -r /dev/ad4s2d
(ee) u dont need to copy the swap partition...
(ff) newfs /dev/mirror/root
(gg) mount /dev/mirror/root /mnt
(hh) cd / ; find . | egrep -v "^\./(usr|var|mnt)/" | cpio -p
--perserve-modification-time /mnt
(ii) for /usr and /var(?) similar...

> 6. dd or tar the backup on the stripe
>
i would use cpio

> 7. Eh..
>
gmirror insert root ad4s1a
...

> 8. ...
>
;-)

-Arne



 
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