Abstract: A storage system, such as a file server, receives a request to perform a write operation that affects a data block. In response, the storage system writes to a storage device the data block together with context information which uniquely identifies the write operation with respect to the data block. When the data block is subsequently read from the storage device together with the context information, the context information that was read with the data block is used to determine whether a previous write of the data block was lost.

Abstract: A technique manages the addition of disks to a volume of a storage system. A disk addition procedure is encapsulated into a DISKADD object conforming to a configuration management framework used to implement a RAID subsystem of the storage system. The DISKADD object is responsible for determining a set of available disks required to satisfy a disk addition request issued by an operator through a user interface of a storage operating system executing on the storage system. Furthermore, the DISKADD object is responsible for monitoring the state of the disks, including preparation/initialization of the disks (e.g., disk zeroing) and possible disk failures, as well as placing those disks into RAID groups of the volume once preparation completes. Persistent storage of the state of a pending disk addition is then accomplished using an implementation of the configuration management framework.

Abstract: A query-based spares management technique enables a storage operating system of a storage system to select disks to be added to one or more RAID groups of a volume. The spares management technique includes an attributes-based disk selection procedure that is performed by the storage operating system in response to an operator-initiated request to add disks to the volume or in response to a demand-driven request resulting from a requirement imposed by the system to add disks to the volume. The disks that are added to the RAID groups of the volume are retrieved from one or more spare pools of disks maintained by the storage system.

Abstract: A storage server stores data in a redundancy group of mass storage devices according to a data redundancy scheme. The redundancy scheme enables reconstruction of all data stored in the redundancy group if N or fewer mass storage devices in the redundancy group contain erroneous data, where N is at least 2. In response to determining that the redundancy group contains erroneous data, N?1 mass storage devices in the redundancy group can be specifically identified as containing the erroneous data.

Abstract: A storage system includes a set of mass storage media and a plurality of functional layers that provide a data storage path between a file system and the set of mass storage media. The storage system can detect that a write issued by the file system was lost by one of the functional layers that provide the data storage path between the file system and the mass storage media.

Abstract: A technique manages the addition of disks to a volume of a storage system. A disk addition procedure is encapsulated into a DISKADD object conforming to a configuration management framework used to implement a RAID subsystem of the storage system. The DISKADD object is responsible for determining a set of available disks required to satisfy a disk addition request issued by an operator through a user interface of a storage operating system executing on the storage system. Furthermore, the DISKADD object is responsible for monitoring the state of the disks, including preparation/initialization of the disks (e.g., disk zeroing) and possible disk failures, as well as placing those disks into RAID groups of the volume once preparation completes. Persistent storage of the state of a pending disk addition is then accomplished using an implementation of the configuration management framework.