Sync a BTC node, quickly
Sync a Bitcoin node for the first time, quickly, on a spinning disk by moving chainstate to an SSD and symlinking to it.
In order to run your own bitcoin node, or lightning node, you'll need to download the entire bitcoin blockchain and then validate it. This takes ages on a magnetic disk due to the random access speed of the contents of the chainstate directory.
To remove this bottleneck, move the chainstate directory to an SSD (its only a few GB) and symlink to it from the bitcoin data directory. More details are on the Bitcoin wiki. When the sync is complete, replace the symlink with the actual chainstate directory.