In general, all data of live clusters will also be stored locally at a PageServer. Only in recovery scenarios will a PageServer not hold the data that is neede

In general, all data of live clusters will also be stored locally at a PageServer. Only in recovery scenarios will a PageServer not hold the data that is needed to serve the requests of a compute node - but that would recover quickly as the local cache of the PageServer is repopulated with data from S3.