Gmirror'd SWAP: no dump?

[Larry Rosenman]

Gavin Atkinson wrote:
> On Thu, 2006-01-19 at 05:49 -0600, Larry Rosenman wrote:
>> Igor Robul wrote:
>>> On Wed, Jan 18, 2006 at 12:44:27PM -0600, Larry Rosenman wrote:
>>>> Are there any plans to support dumping to a gmirror'd swapfile?
>>> Dumping occurs when kernel is in "bad condition", so GEOM can not be
>>> safe used (for example panic in GEOM code).
>>> 
>>> Check archives for  last month of 2005 for longer explanation.
>> 
>> I was afraid of that. What's the recommendation for how to Set up a
>> 2-disk system with mirroring then?
>> 
>> All the HOWTO's I've seen have the entire disk mirrored, including
>> all the pieces. 
>> 
>> My current setup is 3 BSD partitions in 1 FDISK slice.  With the
>> entire disk (da0/da1) mirrored.
>> 
>> How can I set it up to allow dumps?
> 
> If you look at the mirror status, you'll see each disk is assigned a
> priority. 
> 
> In theory, "The component with the biggest priority is used [...] as
> a master component when resynchronization is needed, e.g. after a
> power failure when the device was open for writing." (gmirror(8)). 
> Therefore, if you set dumps to /dev/da0s1b (or whichever swap
> partition is on the disk with the biggest priority), the machine can
> dump to the disk directly, and will end up resyncing to the other
> disk on reboot (which it would have had to do anyway due to the
> panic), and your dump will be doubly safe.    

The problem with this idea is the fact that the da0s1b device is NOT
available:

$ ls -l /dev/da?s1?
ls: /dev/da?s1?: No such file or directory
$

   
-- 
Larry Rosenman                     http://www.lerctr.org/~ler
Phone: +1 512-248-2683                 E-Mail: ler at lerctr.org
US Mail: 430 Valona Loop, Round Rock, TX 78681-3683 US