A storage system according to one preferred embodiment of the present invention is composed of at least a first storage subsystem and a second storage subsystem. Write data from a host computer is duplicated to a first volume of the first storage subsystem and a second volume of the second storage subsystem, and the host computer is composed to be able to access both the first volume and the second volume. Attribute information which is information related to an order of write and/or write capability is set for each volume, and when an access command to the volume is received from the host computer, the storage subsystem determines whether I/O to the first volume and/or the second volume is required or not based on the attribute set for each volume.

A virtualization controller identifies a node that manages a segment to be accessed, and instructs the node to access the segment. A mirror controller of the node instructed to access the segment writes data in the segment managed by the node and in a segment having a mirror relation with the segment managed by the node.

In an approach for establishing metadata for one or more primary devices in a mirroring relationship, one or more computers systems generate a device validity token and establish a mirroring relationship, wherein the mirroring relationship includes identifying one or more primary devices of a plurality of devices in the mirroring relationship. The approach includes the computer systems sending the device validity token to each of a plurality of operating systems in the mirroring relationship for storage in a token store and retrieving a logical device identifier for each of the devices in the mirroring relationship. Furthermore, the approach includes the computer systems generating metadata for each of the primary devices, wherein metadata for each of the one or more primary devices includes at least the device validity token and the logical device identifier for each primary device of the one or more primary devices that generates the metadata.

A data processing system configured to store a plurality of data entities in volatile memories of multiple different computing devices. The data processing system comprises a first computing device having a first volatile memory configured to store a first data entity; and a second computing device having a second volatile memory configured to store a copy of the first data entity. The first computing device is configured to perform: receiving an indication to update the first data entity; after receiving the indication, updating the first data entity in the first volatile memory, and providing to the second computing device an indication to update the copy of the first data entity; and providing an indication that the first data entity has been updated, after receiving information from the second computing device indicating that the copy of the first data entity has been updated in the second volatile memory.

A method, computer system, and computer program product area provided. A computer transmits a query command to a storage descriptor area of a first disk. The first disk belongs to a dual-site data replication system. The dual-site data replication system provides active-active access to a volume of data stored in an active disk and replicated in a backup disk. The computer receives a response to the query command. The response indicates the active disk and the backup disk for the dual-site data replication system. The computer controls an additional copy of the volume of data at a further remote site based on the active disk.

Computer-implemented methods and systems for replication of data between mirrored data sites are provided. An exemplary method may comprise receiving a data object at a mirrored data site, the mirrored data site including one or more data nodes. The data objects are replicated to the one or more data nodes internally. Then, a data object reference associated with the data object is generated. The reference referring to the data object is queued for transmission to all other mirrored data sites. The data object reference associated with the data object is transmitted to the other mirrored data sites. When the data object is received at each mirrored data site, it is replicated to one or more data nodes within the site. After transmitting the data object, the data object reference is discarded.

Disclosed is a data processing and/or storage system. The data processing and/or storage system includes at least two interfaces, wherein each of the at least two interfaces includes a non-dedicated communication port for communicating data to and form external data systems or clients based on a rule base.

Disclosed is a data processing and/or storage system. The data processing and/or storage system includes at least two interfaces, wherein each of the at least two interfaces includes a non-dedicated communication port for communicating data to and form external data systems or clients based on a rule base.

A storage system includes a first storage control device including a first memory being a volatile memory and a first processor, and a second storage control device including a second memory being a non-volatile memory and a second processor, wherein the second processor is configured to receive a first write request to write first data into a first storage device, store the first data into the second memory, and transmit the first data to the first storage control device, the first processor is configured to store the first data into the first memory, and transmit a first notification to the second storage control device, and the second processor is configured to receive the first notification, transmit a first completion notification in response to the first write request, and execute processing to write the first data, stored in the second memory, into the first storage device.

In a previous storage apparatus, differential JNLs are reflected in order of the sequential numbers, to the data volumes thereof. If a first storage apparatus is suspended, it is determined which is newer: the sequential number which the journal recently reflected in a second storage apparatus or the sequential number reflected in a third storage apparatus. In the newer storage apparatus having the newer sequential number, it is determined whether one or more JNLs from the journal having the sequential number next to the sequential number which is not determined to be the newer to the journal having the sequential number determined to be the newer exist, or not. If the result of the determination is positive, from the newer storage apparatus to the previous storage apparatus which is not the newer of the second and the third storage apparatuses, one or more differential JNLs are copied.