Patent ID: 8074035

Claim:
A computer system that provides block-based backup of data, comprising: a plurality of data storages storing block data, wherein the block data corresponds to a data set distributed across multiple data storages, the distributed data set comprising interconnected data residing on different data storages, which is maintained in synchronization, wherein the block data distributed over multiple data storages that have not been backed up is protected prior to writes to these blocks; a backup storage that stores block data without suspending an application program accessing the data; an intermediate data block container that stores block data, wherein the computer system copies a data block from any of the data storages into the intermediate data block container and copies a data block from the intermediate data block container into the backup storage during an online data backup process; wherein: snapshots reflecting a current state of all data storages to be backed up are simultaneously created; a bitmap of data storage blocks located in the data storages that are subject to the data backup is generated, based on the snapshots; a data storage block is copied to the backup storage based on the bitmap of data storage blocks; and a write command that is directed to a data storage block that is subject to the data backup process but has not yet been copied is suspended, old data in the data storage block of the data storages that is the subject of a write command is copied to the intermediate storage container, then the write command writing new data to the data storage block of the data storages is executed and the data storage block containing the old data from the intermediate block data container is subsequently copied to the backup storage; and wherein if the data block that is subject to the backup is unavailable, that data block is marked as invalid and operations are continued with other data blocks in the data storage.