RE: [Xen-users] suspend/resume and live migration I/O mappings

["Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>]

> When suspending a domain and resuming it on a different host 
> or using live migration, what are the I/O configuration 
> requirements of the source and target hosts?   In particular, 
> if using block devices in dom0 for use as domU disks, does 
> the destination host require an identical view of the block 
> devices?   In other words, suppose a SAN LUN seen on /dev/sdc 
> in dom0 on the source host is mapped to a domU for one of its 
> disks, but on the destination host, the same SAN LUN shows up 
> on /dev/sdd in dom0, is there an ability to remap the devices 
> for a domU during the resume or migration?   

You can write a script similar to the 'block-enbd' or 'block-file' that
handles the mapping of some higher-level name down to the local device.

> Same issue for 
> eth devices as the source/destination may not have an 
> identical number of NICs or the network connectivity of NICs 
> may different on the two hosts.  

Again, you can intercept this in 'vif-bridge' if you have special
requirements.

> I suppose the same issue 
> even extends to file based disks in shared NFS or clustered 
> storage - do both source/destination hosts require the same 
> NFS mount points?  

You can intercept this in the 'block-file' script. Note than loopback
files over NFS is a bad idea -- linux just doesn't handle this well.

Best,
Ian

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