A computer-implemented method of protecting data in a protected storage system, the method comprising: storing, in an object-based storage, a replication of the protected storage system from a predetermined time point, in a plurality of replicated content objects of a target disk, wherein a replicated content object stores data of an address space of the protected storage system, wherein a replicated content object can be re-written but cannot be modified; obtaining a copy of data stored on the protected storage system following changes in the protected storage system and metadata related to the stored data; maintaining a journal comprising a plurality of journal content objects and a plurality of metadata objects stored in the object-based storage, by: including the copy of the stored data in a content entry in one or more of the journal content objects; including at least some of the metadata in a metadata entry in one or more of the metadata objects; and associating the metadata entry with the content entry; and periodically applying the data received before a predetermined time window from the journal content objects to at least one replicated content object by obtaining, modifying and re-writing the at least one replicated content object, wherein the journal content objects, the metadata objects and the replicated content objects of the target disk have a fixed size, and wherein periodically applying the data comprises: receiving a time value; examining metadata objects in the journal to identify entries related to last writes to addresses, that occurred before the time value; generating a region-locator structure, said region-locator structure including, for each address, all the writes to that address together with a reference to a content entry in a journal content object that includes data of the last write to the address; and using the region-locator structure to produce the replication of data stored on the protected storage system by: copying data from content entries in the journal for the addresses in the list; and copying data from the target disk for other addresses. storing, in an object-based storage, a replication of the protected storage system from a predetermined time point, in a plurality of replicated content objects of a target disk, wherein a replicated content object stores data of an address space of the protected storage system, wherein a replicated content object can be re-written but cannot be modified; obtaining a copy of data stored on the protected storage system following changes in the protected storage system and metadata related to the stored data; maintaining a journal comprising a plurality of journal content objects and a plurality of metadata objects stored in the object-based storage, by: including the copy of the stored data in a content entry in one or more of the journal content objects; including at least some of the metadata in a metadata entry in one or more of the metadata objects; and associating the metadata entry with the content entry; and including the copy of the stored data in a content entry in one or more of the journal content objects; including at least some of the metadata in a metadata entry in one or more of the metadata objects; and associating the metadata entry with the content entry; and periodically applying the data received before a predetermined time window from the journal content objects to at least one replicated content object by obtaining, modifying and re-writing the at least one replicated content object, wherein the journal content objects, the metadata objects and the replicated content objects of the target disk have a fixed size, and wherein periodically applying the data comprises: receiving a time value; examining metadata objects in the journal to identify entries related to last writes to addresses, that occurred before the time value; generating a region-locator structure, said region-locator structure including, for each address, all the writes to that address together with a reference to a content entry in a journal content object that includes data of the last write to the address; and using the region-locator structure to produce the replication of data stored on the protected storage system by: copying data from content entries in the journal for the addresses in the list; and copying data from the target disk for other addresses. receiving a time value; examining metadata objects in the journal to identify entries related to last writes to addresses, that occurred before the time value; generating a region-locator structure, said region-locator structure including, for each address, all the writes to that address together with a reference to a content entry in a journal content object that includes data of the last write to the address; and using the region-locator structure to produce the replication of data stored on the protected storage system by: copying data from content entries in the journal for the addresses in the list; and copying data from the target disk for other addresses. copying data from content entries in the journal for the addresses in the list; and copying data from the target disk for other addresses.