Lvm – Should swap space be in a logical volume, or directly on disk

Sure, of course it's possible.

dd if=/dev/mygroup-mylv | ssh 192.168.1.103 dd of=/dev/newvgroup-newlv

Boom.

Do yourself a favor, though, and use something larger than the default blocksize. Maybe add bs=4M (read/write in chunks of 4 MB). You can see there's some nitpicking about blocksizes in the comments; if this is something you find yourself doing fairly often, take a little time to try it a few different times with different blocksizes and see for yourself what gets you the best transfer rates.

Answering one of the questions from the comments:

You can pipe the transfer through pv to get statistics about the transfer. It's a lot nicer than the output you get from sending signals to dd.

I will also say that while of course using netcat -- or anything else that does not impose the overhead of encryption -- is going to be more efficient, I usually find that the additional speed comes at some loss of convenience. Unless I'm moving around really large datasets, I usually stick with ssh despite the overhead because in most cases everything is already set up to Just Work.

The LVs were still mounted on startup because the initrd has an older lvm.conf without the faulty filter. The new filter will prevent LVM commands from working, but it won't break LVs that have already been mounted.

The initrd will be updated with your current lvm.conf when you update your kernel, so make sure you fix the filter before then.