Re: syncer panic

From: Robert Watson <rwatson_at_freebsd.org>
Date: Sat, 13 Dec 2003 08:33:57 -0500 (EST)
On Sat, 13 Dec 2003, Thierry Herbelot wrote:

> Le Saturday 13 December 2003 11:11, Tim Bishop a écrit :
> >
> > As I've said, I am using vinum to mirror my swap. However, I set dumpdev
> 
> Vinum to mirror also the swap ? Please explain what you are trying to
> achieve ? 

Presumably uptime via fault tolerance: the goal of putting swap and
temporary storage on a mirrored array is to avoid a single disk failure
from taking you down.  Losing your swap partition can have disastrous
consequences on any data stored in the partition, including application
data...  That said, I believe the problem being experienced here is that
the swap subsystem currently expects to talk to a GEOM object, and when it
looks at Vinum it finds a non-GEOM object.  This can probably be worked
around by tricking GEOM into sticking a GEOM wrapper on the Vinum
partition you want to use for swap, such as using a Vinum partition as
backing for a vnode-backed md device.  That said, I can't reach my test
boxes at work that I use for occasional Vinum testing due to a firewall
outage, so I can't test it right this moment.  The long-term fix is to
make GEOM speak the disk(9) API at the top end, rather than the character
device API. 

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert_at_fledge.watson.org      Senior Research Scientist, McAfee Research



> I built a fully-mirrored machine (to check what the handbook said about 
> booting from a mirrored root), but /tmp was still a simply striped partition 
> (no mirror), like swap, where I left the OS swap manager use two partitions, 
> like you could do when having two non-vinumed disks :
> in /etc/fstab :
> /dev/ad0s3b     none        swap    sw      0   0
> /dev/ad2s3b     none        swap    sw      0   0
> 
> With this kind of setup, all important data are (suposed to be) written to 
> both physical disks, and all remaining info will be lost in case of a 
> failure.
> 
> 	TfH
> 
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Received on Sat Dec 13 2003 - 04:34:19 UTC

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