The suggested Storable is core and should work fine, but there are many more - often much nicer - ways to store persistent hashes. IMHO a more modern and better way is Sereal.

Not that for some, complex keys of code refs in values may cause havoc.

Personally I like to tie my hashes if I need persistence.

With my Tie::Hash::DBD you can even tie your hashes to be stored in a database. See this script (which you should modify to your needs) to benchmark the available methods. this page shows benchmarks for the methods I found on my system (higher values in the last column are better).