Xen users - Jul 2005 - DomU: Unable to find swap-space signature

Hi list,

	my Debian DomU is unable to find it''s swap space and
gives ''Unable to find swap-space signature''. I allocated it 
with ''disk =
[''phy:sda8,sda8,rw'',''phy:sda9,sda9,rw'']''
in it''s
config file and put it in /etc/fstab but swapon gives the afore
mentioned message. Anybody got a clue?

Sincerely,

Jan.

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John Smith wrote:
>Hi list,
>
>	my Debian DomU is unable to find it''s swap space and
>gives ''Unable to find swap-space signature''. I allocated
it
>with ''disk =
[''phy:sda8,sda8,rw'',''phy:sda9,sda9,rw'']''
in it''s
>config file and put it in /etc/fstab but swapon gives the afore
>mentioned message. Anybody got a clue?
>
>  
>
Assuming you DID create and allocate /dev/sda9 on domain-0 (e.g. on your 
real disk) for dom-U''s swap space, try

mkswap /dev/sda9

IMHO, the common method is to export block device (partition, loopback 
file, or LVM) in domain-0 to dom-U as sda1/2 or hda1/2,
so instead of

disk =
[''phy:sda8,sda8,rw'',''phy:sda9,sda9,rw'']

it might be better to use

disk = [''phy:sda8,sda1,w'',''phy:sda9,sda2,w'']

BTW, "w" should be enough

Regards,

Fajar


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Not sure if someone already addressed your question. If not....

mkswap /dev/sdXY

if you haven''t already. Sounds like it just hasn''t been
formatted into
swap space yet.

Hope this helps ya out,
John Fairbairn
> Hi list,
>
> 	my Debian DomU is unable to find it''s swap space and
> gives ''Unable to find swap-space signature''. I allocated
it
> with ''disk =
[''phy:sda8,sda8,rw'',''phy:sda9,sda9,rw'']''
in it''s
> config file and put it in /etc/fstab but swapon gives the afore
> mentioned message. Anybody got a clue?
>
> Sincerely,
>
> Jan.
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>


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> On Wed, 6 Jul 2005 05:40:20 +0200
> "John Smith" wrote:
> > 	my Debian DomU is unable to find it''s swap space and
> > gives ''Unable to find swap-space signature''. I
allocated it
> > with ''disk =
[''phy:sda8,sda8,rw'',''phy:sda9,sda9,rw'']''
in it''s
> > config file and put it in /etc/fstab but swapon gives the afore
> > mentioned message. Anybody got a clue?
> 
> "John Fairnbairn" wrote:
> 
> Not sure if someone already addressed your question. If not....
> 
> mkswap /dev/sdXY
> 
> if you haven''t already. Sounds like it just hasn''t been
formatted into
> swap space yet.
>
> "Fajar A. Nugraha" wrote: 
>
> Assuming you DID create and allocate /dev/sda9 on domain-0 (e.g. on your 
> real disk) for dom-U''s swap space, try
> 
> mkswap /dev/sda9
> 
> IMHO, the common method is to export block device (partition, loopback 
> file, or LVM) in domain-0 to dom-U as sda1/2 or hda1/2,
> so instead of
> 
> disk =
[''phy:sda8,sda8,rw'',''phy:sda9,sda9,rw'']
> 
> it might be better to use
> 
> disk =
[''phy:sda8,sda1,w'',''phy:sda9,sda2,w'']
> 
> BTW, "w" should be enough
Both Fajar and John were dead on : the swapspace wasn''t initialized.

For future reference : 

- check swap space usage with ''cat /proc/swaps''
- initialize swap space with ''mkswap
/dev/<swapfilesystem>''
- place swap space filesystem in /etc/fstab :
   ''/dev/<swapfilesystem> none swap sw 0 0''
- activate with ''swapon -a''

Cool tip, Fajar, on the numbering, that way you can use the same
DomU internal configuration in all virtual vms.

Thanks guys.

Sincerely,

Jan.

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