Is it possible to DD one server to another? Maybe through SSH? I've looked around and I have seen examples of DD using SSH from local to server and vice versa, but is it possible to do it from server to server?
Another question that relates is what software does Digital Ocean use to create the snapshots of their servers that can then be later restored?
Thanks,
Sure, though it's a little clunky. You can do something like:
$ ssh server1 'dd if=/some/file' | ssh server2 'dd of=/new/file/path'
and it'll work. You could tweak the block side on both sides (pass bs=1m or whatever to both dd commands) for a speedup with some testing.
No idea about Digital Ocean: you'll probably want to ask them, or start another question here if you think someone might know.
A bit more efficient then SSH would be netcat nc as you wouldn't have the overhead of encrypting/decrypting your streams.
From the manual, create a listener on port 12345 on one side and make sure it is open in your firewall:
nc -l 12345 > filename.out
And then feed the data from your source server:
nc host.example.com 12345 < filename.in
The connection should close automatically after the transfer is complete.
In response to your comment to Bill, if you want to create identical machines by cloning the disks, that is typically done from outside the virtual machine, via the hypervisor, and not from within the OS.
The above will work well enough to clone disks/partitions/volumes from within the running OS as long as they are not mounted at the time, instead of files use the device entries in /dev/, but you can't use it clone the device that contains your root file system.
