A device for backing up data in a computer infrastructure offering disaster recovery functions, said device being characterized in that it comprises the following means, - at least a first and a second sets of storage means; - at least a first (CTL 1) and a second (CTL 2) memory controller, said first memory controller being associated with said first set of storage means and said second memory controller being associated with said second set of storage means; and - microcontroller (μP) configured: ∘ for duplicating a stream of commands and data sent to said first memory controller towards said second memory controller in a normal use mode enabling a local replication of data in said second set of storage means; ∘ for addressing a stream of separate commands and data to each of said first and second memory controllers in a remote replication mode in such a way that elements of data are read/write-accessible in each disc of the first set of disks, by a first external device, and that, independently, the same or other data elements are read-only accessible in each disc of the second set of disks, by a second external device; and ∘ for synchronizing a set of data stored in said second set of storage means with a set of corresponding data stored in said first set of storage means before a local replication and after a remote replication by the second memory controller, from data of the second set of storage means; the microcontroller being further configured for deactivating the synchronization of the local replication of data between the two controllers, during the remote replication phase and for reactivating the synchronization of the local replication of data between the two controllers when the remote replication phase is ended. - at least a first and a second sets of storage means; - at least a first (CTL 1) and a second (CTL 2) memory controller, said first memory controller being associated with said first set of storage means and said second memory controller being associated with said second set of storage means; and - microcontroller (μP) configured: ∘ for duplicating a stream of commands and data sent to said first memory controller towards said second memory controller in a normal use mode enabling a local replication of data in said second set of storage means; ∘ for addressing a stream of separate commands and data to each of said first and second memory controllers in a remote replication mode in such a way that elements of data are read/write-accessible in each disc of the first set of disks, by a first external device, and that, independently, the same or other data elements are read-only accessible in each disc of the second set of disks, by a second external device; and ∘ for synchronizing a set of data stored in said second set of storage means with a set of corresponding data stored in said first set of storage means before a local replication and after a remote replication by the second memory controller, from data of the second set of storage means; ∘ for duplicating a stream of commands and data sent to said first memory controller towards said second memory controller in a normal use mode enabling a local replication of data in said second set of storage means; ∘ for addressing a stream of separate commands and data to each of said first and second memory controllers in a remote replication mode in such a way that elements of data are read/write-accessible in each disc of the first set of disks, by a first external device, and that, independently, the same or other data elements are read-only accessible in each disc of the second set of disks, by a second external device; and ∘ for synchronizing a set of data stored in said second set of storage means with a set of corresponding data stored in said first set of storage means before a local replication and after a remote replication by the second memory controller, from data of the second set of storage means;