The present technology includes a memory controller that allocates a new buffer memory area in a buffer memory or stores temporarily stored data in the buffer memory into a memory device based on a state of an auxiliary power device that supplies power to the memory device and the memory controller, and a power state of a host.

Synchronizing metadata among storage systems synchronously replicating a dataset, where synchronizing the metadata includes: receiving, at a first storage system of the storage systems, an I/O operation directed to the dataset; determining, in dependence upon the I/O operation, a metadata update describing a mapping of segments of content to a virtual address within a storage object, wherein the storage object includes the dataset; and synchronizing metadata on a second storage system of the storage systems by sending the metadata update to the second storage system to update a metadata representation on the second storage system in accordance with the metadata update.

A device and method for dispensing a friction-coefficient-optimizing mixture of at least one lubricant and at least one grit into the gap between a rail wheel of a rail vehicle and a rail. The device includes a reservoir for the lubricant, a reservoir for the grit, a metering unit for metering the lubricant, a metering unit for metering the grit, a delivery apparatus for delivering the lubricant, a delivery apparatus for delivering the grit, and a common dispensing nozzle. The apparatus for delivering the lubricant and the apparatus for delivering the grit are separate from each other and end in the common dispensing nozzle, the friction-coefficient-optimizing mixture therefore not being formed until the dispensing, and an additional compressed air line is provided, which ends in the common dispensing nozzle.

Determining active membership among a set of storage systems synchronously replicating a dataset, where determining active membership includes: determining that a membership event corresponds to a change in membership to the set of storage systems synchronously replicating the dataset; applying, in dependence upon the membership event, one or more membership protocols to determine a new set of storage systems to synchronously replicate the dataset; and for one or more I/O operations directed to the dataset, applying the one or more I/O operations to the dataset synchronously replicated by the new set of storage systems.

Managing connectivity to synchronously replicated storage systems, including: identifying a plurality of storage systems across which a dataset is synchronously replicated; identifying a host that can issue I/O operations directed to the dataset; identifying a plurality of data communications paths between the host and the plurality of storage systems across which a dataset is synchronously replicated; identifying, from amongst the plurality of data communications paths between the host and the plurality of storage systems across which a dataset is synchronously replicated, one or more optimal paths; and issuing, to the host, an identification of the one or more optimal paths.

Automatic storage system configuration for mediation services that includes: determining that a particular storage system of the storage systems is not configured to request mediation from a mediation target for mediation between storage systems synchronously replicating a dataset; requesting, by the particular storage system from a configuration service, configuration information indicating one or more service handles for a mediation service; and configuring, in dependence upon the one or more service handles received from the configuration service, a mediation handler to communicate with the mediation service responsive to detecting a communication fault with one of the storage systems.

Methods and apparatus for efficiently storing and accessing secure data are disclosed. The method of storing includes encrypting data utilizing an encryption key to produce encrypted data, performing deterministic functions on the encrypted data to produce deterministic function values, masking the encryption key utilizing the deterministic function values to produce masked keys and combining the encrypted data and the masked keys to produce a secure package. The method of accessing includes de-combining a secure package to reproduce encrypted data and masked keys, selecting a deterministic function, performing the selected deterministic function on the reproduced encrypted data to reproduce a deterministic function value, de-masking a corresponding masked key utilizing the reproduced deterministic function value to reproduce an encryption key, and decrypting the reproduced encrypted data utilizing the reproduced encryption key to reproduce data.

Embodiments are directed to determining active membership among a set of storage systems synchronously replicating a dataset. Determining active membership among a set of storage systems synchronously replicating a dataset includes determining that a membership event corresponds to a change in membership to the set of storage systems synchronously replicating the dataset. Determining active membership further includes applying, in dependence upon the membership event, one or more membership protocols to determine a new set of storage systems to synchronously replicate the dataset. Determining active membership also includes, for one or more I/O operations directed to the dataset, applying the one or more I/O operations to the dataset synchronously replicated by the new set of storage systems.

Determining active membership among storage systems synchronously replicating a dataset, where determining active membership includes: detecting, by a particular storage system of the storage systems, a communication fault with one or more of the storage systems, where the particular storage system is configured to request mediation from a mediation target; determining that at least one of the one or more storage systems is configured to request mediation from the mediation target responsive to the communication fault; and responsive to determining that one or more of the storage systems is configured to request mediation from the mediation target, determining whether to request mediation from the mediation target.

Mediating between storage systems synchronously replicating a dataset, including: requesting, by a first storage system in response to detecting a triggering event, a lock for a shared resource from a mediation service; requesting, by a second storage system in response to detecting the triggering event, the lock for the shared resource from the mediation service; and responsive to acquiring the lock from the mediation service, the first storage system, instead of the second storage system, processing data storage requests directed to the dataset that is synchronously replicated across the first storage system and the second storage system.