Embodiments are generally directed to high capacity energy backed memory with off device storage. A memory device includes a circuit board; multiple memory chips that are installed on the circuit board; a controller to provide for backing up contents of the memory chips when a power loss condition is detected; a connection to a backup energy source; and a connection to a backup data storage that is separate from the memory device.

In one set of embodiments, a storage system can execute a repair process for a first component of a file or object stored on the storage system, where the repair process is initiated in response to the first component becoming inaccessible by the storage system, and where the file or object is split across a plurality of components including the first component. The executing can include, for each chunk in an address space of the first component starting from an initial chunk pointed to by a cursor: (1) determining whether the chunk is mapped to the first component, (2) if the chunk is mapped to the first component, copying data for the chunk from a mirror copy of the first component to a second component in the plurality of components, and (3) updating the cursor to point to a next chunk in the address space.

A storage system includes a first storage controller including a plurality of main storage media and one or more processor cores, and a second storage controller including a plurality of main storage media and one or more processor cores and performing communication with the first storage controller. Storage areas of the main storage media in the first storage controller are allocated to an address map. In response to the occurrence of failures in one or mode main storage media of the main storage media of the first storage controller, the first storage controller performs restarting to reallocate the storage areas of the main storage media excluding one or more main storage media having caused the failures to an address map reduced than before the occurrence of the failures. The second storage controller continues operating during the restarting of the first storage controller.

A failure in a main site is recovered by operating in the same operational environment as a sub site. A remote copy system includes: a first storage system providing a main site; and a second storage system providing a sub site. A storage controller stores data and an operation processed in the main site as a main site journal, sends the main site journal to the sub site for sequential processing, stores data and an operation processed in the sub site as a sub site journal after a failover to the sub site is performed, and cancels an unreflected operation that is not processed in the sub site after being stored in the main site journal prior to the failover in the main site and sequentially processes the sub site journal in the main site, when a failback to the main site is performed.

A mirroring device that can improve, even when two storage devices to which an upper limit is set for the number of rewrites of data are used, the fault tolerance of the mirroring device while preventing one of the storage devices from reaching the lifetime thereof early. A mirroring device comprises two storage devices to which an upper limit is set for the number of rewrites of data. Remaining writable amounts of the data in the storage devices are acquired respectively from total amounts of the data written in the respective storage devices. When it is determined that a difference between the respective acquired remaining writable amounts is less than a predetermined value, the respective storage devices are controlled such that the difference becomes equal to or more than the predetermined value.

According to one aspect of the present invention, there is provided a method for performing storage control. Member storage media and a hot spare storage medium are identified in a storage system. The member storage media are members of a storage medium array, and the hot spare storage medium is for joining in the storage medium array when a member storage medium fails. Data on a member storage medium having a write amplification effect is migrated to the hot spare storage medium. In the member storage medium having a write amplification effect, an erase operation is performed on a storage medium where the migrated data is located. Embodiments of the present invention can alleviate adverse impact caused by a write amplification effect.

Provided are a computer program product, system, and method for using mirror indicators to determine whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume. A table is read. The table is maintained by a primary controller managing the primary volume that includes a mirror indicator for each of a plurality of tracks in at least one data set configured in the primary volume indicating whether a track is to be mirrored to the secondary volume. Record sets are read from a cache of the primary controller for the tracks in primary volume having the mirror indicators in the table indicating that the track is to be mirrored. The write data in the read record sets is applied to tracks in the secondary volume mirroring the tracks in the primary volume.

A daisy-chain storage synchronization (DSS) system and method that permits a daisy-chain of interconnected pass-thru disk drive controllers (PTDDCs) each connected to a SATA local disk drive (LDD) disk storage element (DSE) to support state synchronization within PTDDCs in the daisy-chain is disclosed. The PTDDCs within the daisy-chain are configured to individually maintain drive state information (DSI) relating to the LDD as well as chain state information (CSI) relating to the individual PTDDCs within the daisy-chain. This state information may be modified on receipt of out-of-band signaling (OBS) from other PTDDC elements up the daisy-chain as well as OBS from other PTDDC elements down the daisy-chain, CSI is determined in part by conventional SATA OBS state register protocols that are modified by internal state registers (ISR) in each individual PTDDC daisy-chain element so as to make the DSS transparent to existing SATA OBS single-disk standard hardware command protocols.

In an embodiment, a data processing method comprises: in a computer executing a supervisor program, the supervisor program establishing different memory access permissions comprising any combination of read, write, and execute permissions for one or more different regions of memory of a first domain, receiving a request from a process to execute a particular memory page of the regions of memory, the particular memory page comprising a memory access permission set to read-writeable or read-only, throwing an execute fault for the particular memory page, performing one or more responsive actions to restore execution access or content of the particular memory page, and after performing the one or more responsive actions, setting the memory access permission to execute only.

A data storage system has at least two universal nodes each having CPU resources, memory resources, network interface resources, and a storage virtualizer. A system controller communicates with all of the nodes. Each storage virtualizer in each universal node is allocated by the system controller a number of storage provider resources that it manages. The system controller maintains a map for dependency of virtual appliances to storage providers, and the storage virtualizer provides storage to its dependent virtual appliances either locally or through a network protocol (N_IOC, S_IOC) to another universal node. The storage virtualizer manages storage providers and is tolerant to fault conditions. The storage virtualizer can migrate from any one universal node to any other universal node.