[Sheepdog] qemu-img convert slowness and high availability status

krimson krims0n32 at gmail.com
Mon Jun 13 23:35:32 CEST 2011

Hi again :)

I was converting an LVM based image to sheepdog using:

# qemu-img convert /dev/vmvg/web sheepdog:web

and noticed it took 2.5 hours to complete. The image is 8GB in size. The 
sheepdog/corosync network is a direct Gbit link between two nodes. Any 
idea as to why this is taking so long ? Small blocksize perhaps ? The 
cluster is using copies=2. Using sheepdog from git (0.2.3) and qemu-kvm 

Another question regarding the state of high availability in sheepdog, I 
noticed it is possible to specify multiple sheepdog hosts in my qemu XML 
definition, and it defaults to localhost. I would like to avoid 
specifying multiple sheepdog hosts in the XML definition if possible and 
was wondering what happens to the VMs when the sheep daemon dies for 
example. The entire node failing would not be a problem I guess as the 
remaining node would then startup the VMs that were running on the 
failed node.


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