Essentially, PCI DSS is not concerned with disaster recovery. PCI doesn't care if transactions can be recovered; PCI DSS only cares about whether sensitive authentication data (SAD) and cardholder data (CHD) are secure.
PCI Requirement 12.8 focuses on vendor management and mandates that companies develop and execute policies and processes to manage service providers with whom cardholder data is shared or who may compromise cardholder data security.