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Date:      Wed, 7 Aug 2002 12:02:27 -0400
From:      Rob Ellis <rob@web.ca>
To:        Danny Pansters <danny@ricin.com>
Cc:        shooverfbn@442spot.com, freebsd-questions@freebsd.org
Subject:   Re: Questions about vinum and failure of root partition
Message-ID:  <20020807160227.GB53552@web.ca>
In-Reply-To: <200208071628.27577.danny@ricin.com>
References:  <200208070101.g7711iU06306@clunix.cl.msu.edu> <005e01c23dcb$061acbb0$6602a8c0@swbell.net> <20020807132232.GA47309@web.ca> <200208071628.27577.danny@ricin.com>

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the advantage of using a slice for the freebsd system
partitions is just that you can copy it with dd. otherwise
you need a script to mount, dump|restore, and unmount
the backup partitions (because you don't want them in
/etc/fstab).

it occurred to me that putting swap on the boot slice
isn't such a good idea -- better to put it on the
data slice.

i'm not sure about putting /usr on the vinum mirror as 
i've seen recommended -- you often want /usr in
single user mode. maybe symlink off /usr/home /usr/src
/usr/obj /usr/ports /usr/local to a vinum partition, which
leaves you with more or less (?) static files in /usr.

- rob

On Wed, Aug 07, 2002 at 04:28:27PM +0200, Danny Pansters wrote:
> On Wednesday 07 August 2002 15:22, Rob Ellis wrote:
> > one workaround for having to have a non-mirrored boot
> > partition with 2 disks is to put 2 slices on each
> > disk -- one for fbsd system partitions, and one for
> > mirrored data...
> >
> >  ad0s1, ad2s1 -> small bootable slices for os partitions
> >  ad0s2, ad2s2 -> rest of the disk for mirrored data partitions
> >
> > install fbsd on ad0s1, with partitions for / and swap
> > and maybe tmp. partition ad2s1 the same way. create
> > your vinum mirror using partitions on ad0s2 and ad2s2
> > and symlink /var and whatever else you want to directories
> > on the mirror.
> 
> More than one slice per drive can be used but are not needed. If using only 
> slice 1 on both disks, give both of them an daN(s1)a partition and dump or 
> copy da0a to da1a. Make da1a bootable and keep both in sync (IMHO a daily 
> dump should suffice). Keep the backup root partition unmounted except when 
> dumping/copying/synching data. Mirror other partitions (d and up) through 
> vinum.
> 
> root@server.ricin.net [/root] # df
> Filesystem        1K-blocks    Used    Avail Capacity  Mounted on
> /dev/da0s1a          508143   80898   386594    17%    /
> /dev/vinum/vinum0   1016170   23130   911747     2%    /var
> /dev/vinum/vinum1   2032490 1195426   674465    64%    /usr
> /dev/vinum/vinum2  13318721    5576 12247648     0%    /home
> procfs                    4       4        0   100%    /proc
> 
> If da1a gets mounted df also has:
> /dev/da1a            508143  163535   303957    35%    /backup_root
> (used size differs because I don't let the the original dump and 
> restoresymtable be deleted)
> 
> >
> > then create a backup of the fbsd partitions on
> > the first disk, copying everything from ad0s1 to ad2s1:
> >
> >   dd if=/dev/ad0s1 of=/dev/ad2s1 bs=102400
> >
> > fsck the newly copied filesystems:
> >
> >   # a, e... are partitions
> >   for i in a e f g h ; do fsck -y /dev/ad2s1$i ; done
> >
> > install ad0's master boot record to ad2
> >
> >   fdisk -B /dev/ad2
> >
> > and now the second disk is a bootable copy of the
> > first; if the first disk fails, you swap the cables
> 
> Exactly. BUT you wouldn't swap cables or disks. If disk0 doesn't boot but 
> instead disk1 has to, by that time your former disk1 *becomes* disk0 :)
> Otherwise, both root partitions would need different fstabs. I have only 
> tested this by unplugging disk0 on reboot but I would expect hardware failure 
> to have the same result, only perhaps after hours of getting sicker and 
> sicker until it reboots itself...
> 
> > on the disks (make the secondary the primary)
> > and reboot -- the os and vinum come back up.
> >
> > - rob
> >
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > with "unsubscribe freebsd-questions" in the body of the message
> 
> Sorry for not CC'ing list. It doesn't like my mailserver on local network and 
> I don't like changing that ;-) Feel free to quote if useful.
> 
> 
> -- 
> DaN
> 
> Shut up & listen. http://stations.mp3s.com/stations/180/ricin_radio.html

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