Outsourcing of financial services processing has been a big business for decades. However it is usually provided to small/medium banks or credit unions by speci

Outsourcing of financial services processing has been a big business for decades. However it is usually provided to small/medium banks or credit unions by specialized firms or by big banks. A big bank will usually do its own ledger processing. A good configuration is to process in two pairs of data centers more than 200 miles apart in different electric utility interconnection regions, e.g. Arlington/Fort Worth and Dayton/Springfield. Archival storage of transactions may involve additional centers. https://en.wikipedia.org/wiki/IBM_Parallel_Sysplex#Geographically_Dispersed_Parallel_Sysplex https://en.wikipedia.org/wiki/IBM_Parallel_Sysplex#Geographi...