US Patent 9135123 Managing global data caches for file system

A method is used in managing global data caches for file systems. Space is allocated in a volatile memory of a data storage system to a global data cache that is configured to store a set of data objects for a plurality of different file systems. The set of data objects is accessed by the plurality of different file systems. Contents of a file of a file system are stored in a data object in the global data cache upon receiving a write I/O request for the file. A copy of the data object and information for the data object are stored in a persistent journal that is stored in a non-volatile memory of the data storage system. Contents of the file are updated on a storage device based on the data object stored in the global data cache and information stored in the persistent journal.