You can just create a backup of the
datadir folder, which could be saved on another hard drive in case your node’s chain state becomes corrupted. In case of corruption, just copy the saved data into the appropriate folder, and your node will then sync from that point in history, rather than starting from scratch. The
datadir can be specified in your
bitcoin.conf file, but will otherwise be found in the default path.
NOTE: you’ll want to stop the node before starting to copy the files. The normal operation of a node includes a lot of ~random reads and writes to the data directory files, so you’ll want to stop the node first to eliminate the chance of corrupting the data during the copy.