I have two external disks, each with a copy of the Monero blockchain. Most of the time, one of the disks sits in a cupboard and its copy of the blockchain lags behind. Every few days, I plug it in and restart monerod with a suitable argument to
My internet connection is slow, so the efficient way to synchronize my lagging copy against my synchronized copy would surely be something purely local. Perhaps I could run two instances of monerod on the same machine, with settings that cause one of my disks to synchronize against the other; but I don't know what command-line arguments to use. Can someone provide an example?
Or, if there's a better way, what is it? For instance, are there generic computer backup protocols that can update the lagging file by reference to the up-to-date file?
Edit: user36303 has previously provided two good answers to this question. I'm accepting jtgrassie's answer (below) though, because it works using monerod itself, i.e. with no requirement to install anything else.