An embodiment for operation of an emulated electrically erasable (EEE) memory system includes a memory controller configured to identify a first quick record of a stack of quick records as a present record, wherein the stack of quick records are stored in a non-volatile portion of memory, the first quick record has a quick record status identifier (ID) that indicates the stack of quick records has not been qualified, determine a record status of a next record after the present record in the non-volatile portion of memory, and in response to a determination that the next record has a blank record status ID: update the next record from the blank record status ID to the quick record status ID, wherein the blank record status ID indicates that the next record is part of the stack of quick records, and qualify the present record using the plurality of program steps.

A redundant memory for use with an instrument arranged to acquire and store data while underwater. Such an instrument comprises a main housing which contains instrument electronics that acquires and may process data received from one or more sensors, with a primary memory located within the main housing and arranged to store at least some of the acquired and/or processed data, and a secondary memory which stores a copy of the data stored in the primary memory. The instrumentation may be arranged to write data to the primary and secondary memories contemporaneously in either a burst or continuous mode, or with primary memory backed up to secondary memory periodically and/or in response to the occurrence of a triggering event. The instrument may comprise a second housing within which the secondary memory is located. The main and second housings may be contained within a common enclosure.

Techniques providing I/O control involve: in response to receiving an I/O request, detecting a first set bits for a stripe in a RAID. The RAID is built on disk slices divided from disks. The stripes include extents. Each of the first set bits indicates whether a disk slice where a corresponding extent in the stripe is located is in a failure state. The techniques further involve determining, from the stripe and based on the first set bits, a first set of extents in the failure state and a second set of extents out of the failure state. The techniques further involve executing the I/O request on the second set of extents without executing the I/O request on the first set of extents. Such techniques can simplify storage bits in I/O control, support the degraded stripe write request for the RAID and enhance performance executing the I/O control.

A data center includes: a server including a control plane; a data plane that is configured to receive network connection information from the control plane; and a storage group including a plurality of first storage devices. The data plane may be configured to set connections between the server and the plurality of first storage devices based on the network connection information corresponding to each first storage device of the plurality of first storage devices.

An information processing apparatus including a removable storage device for storing data includes a control unit that determines whether communication is possible with the storage device and, if communication with the storage device is determined not to be possible, prohibit data from being written to the storage device. When the information processing apparatus is started up, the control unit again determines whether communication is possible with the storage device to which the control unit prohibits data writing and permits data writing to the storage device if communication with the storage device is determined to be possible.

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.

Provided are a computer program product, system, and method for using mirror indicators to indicate whether to mirror tracks in a data set in a primary volume mirrored to a secondary volume. A table includes a mirror indicator for each of a plurality of tracks in at least one data set in the primary volume indicating whether a track is to be mirrored to the secondary volume. In response to a write command of write data for one of the tracks in the primary volume, creating a record set in a cache for the primary volume including write data for the track to transfer to the secondary volume in response to the mirror indicator for the track indicating that the track is to be mirrored. The write data in the record set is transferred from the cache to the secondary volume.

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.

A controller monitors access frequencies of address ranges mapped to a data storage array. Based on the monitoring, the controller identifies frequently accessed ones of the address ranges that have lower associated wear, for example, those that are read more often than written. In response to the identifying, the controller initiates copying of a dataset associated with the identified address ranges from the data storage array to a spare storage device while refraining from copying other data from the data storage array onto the spare storage device. The controller directs read input/output operations (IOPs) targeting the identified address ranges to be serviced by access to the spare storage device. In response to a failure of a failed storage device among the plurality of primary storage devices, the controller rebuilds contents of the failed storage device on the spare storage device in place of the dataset associated with the identified address ranges.

A data recovery method recovers corrupted data after a disaster event in a storage facility operating with deduplication in which copies of data are maintained between volumes through a copy services relationship. The deduplication operates with referencing domains, each having a source grain containing a reference pointing to a location where data is stored and referrers pointing to the source. The data recovery method identifies any source that is pointing to data which is corrupt and then establishes whether a copy services relationship exists between the referencing domain of the source with corrupted data and another referencing domain, in which case the other referencing domain will have a copy of the corrupted data. Provided that the copy is valid, it is written across to replace the corrupted data. The method allows corrupted source data to be recovered without having to perform a full resync or restore.