Abstract: A system and method for a file server to allocate spare disks in a network storage system. The method determines the available spare disks and first selects those disks that satisfy one or more required rules. The method sorts the spare disks by a set of ordered policies to determine a highest-ranked disk that is then selected as the spare to be utilized. If multiple disks are equally ranked, one of the equally ranked disks is randomly chosen to be the spare disk allocated.

Abstract: A system and method for allowing more rapid takeover of a failed filer by a clustered takeover partner filer in the presence of a coredump procedure (e.g. a transfer of the failed filer's working memory) is provided. To save time, the coredump is allowed to occur contemporaneously with the takeover of the failed filer's regular, active file service disks by the partner so that the takeover need not await completion of the coredump to begin. This is accomplished, briefly stated, by the following techniques. The coredump is written to a single disk that is not involved in regular file service, so that takeover of regular file services can proceed without interference from coredump. A reliable means for both filers in a cluster to identify the coredump disk is provided, which removes takeover dependence upon unreliable communications mechanisms.

Abstract: A system and method for transferring ownership of a volume in a networked storage environment. The method first moves the disks that comprise the volume being transferred from a source-owned state to an un-owned state. Next the disks are moved to a destination-owned state. Each step of the transfer process completes on all disks before the next step begins to ensure consistency and disks that have conflicting owners. Alternate embodiments include logging by the source and destination nodes to permit a resumption of the transfer if one node becomes inactive during the transfer.

Abstract: A system and method for coordinated bringup of a storage appliance in a storage appliance cluster. The repaired storage appliance, during its initialization, sets a variety of state values in a predetermined memory location comprising a state data structure, which is detected by a remote direct memory access read operation by the surviving storage appliance. By the use of the RDMA operations, the repaired storage appliance and surviving storage appliance coordinate the bringup and giveback of data servicing functionality.

Abstract: This invention provides a system and method for selecting and communicating a single disk (a “coredump disk”) for use in a coredump procedure by a failed file server (or filer). A selection method on the failed filer determines the “best candidate” coredump disk according to a predetermined set of criteria. For example, the available disks that can receive coredump data are located and ordered so as to prefer disks that best match the coredump data size requirement, are least likely to be needed for normal service by the server; and require the least preparation to receive coredump data. Appropriate attributes on the selected coredump disk are written to indicate that a coredump is in progress, and the location of the coredump data. Upon reboot of the failed filer (or takeover by a cluster partner), the coredump disk is identified and the coredump data recovered by reading back appropriate attributes.

Abstract: A system and method for determining a disk ownership model to be utilized by a storage system is disclosed. The storage system and method determines the individual disk ownership of each accessible disk to the storage system. If the number of disks utilizing a first ownership model is exceeded, the storage system utilizes the first ownership model. Otherwise, the storage system utilizes a second ownership model.

Abstract: A system and method of storing data for use by storage operating systems in memories associated with switch ports. The data is written to a switch port memory, which is readable by all devices connected to the switch, and by all devices connected to a switching fabric containing that switch. When a device connected to the switching fabric requires the information, the device retrieves the stored information from the switch-port memory, without the need for any interaction of the device that originally wrote the data.

Abstract: A system and method for a file server to allocate spare disks in a network storage system. The method determines the available spare disks and first selects those disks that satisfy one or more required rules. The method sorts the spare disks by a set of ordered policies to determine a highest-ranked disk that is then selected as the spare to be utilized. If multiple disks are equally ranked, one of the equally ranked disks is randomly chosen to be the spare disk allocated.

Abstract: A technique includes a set of procedures utilized during the transfer of service of a failed storage system to a surviving storage system of a cluster failover (CFO) configuration during a system outage, such as a disaster scenario. The procedures are executed by a RAID subsystem of the surviving storage system during disaster takeover, storage healing and node restart operations. The procedures prevent the possibility that clients accessing the storage system will see out-of-date versions of the data either during transfer of service of the system during the disaster scenario or subsequently after the storage system is healed and service on the failed system has been restored.

Abstract: A storage system includes a plurality of mass storage devices and a first storage server head to access the mass storage devices in response to client requests, wherein the first storage server head has ownership of the plurality of mass storage devices. Ownership of at least one of the mass storage devices is reassigned to a second storage server head independently of how the second storage server head is connected to the plurality of mass storage devices.

Abstract: The present invention provides a system and method for verifying disconfigurations of file servers by performing a verification in real-time after any disk event which modifies the disk configuration. A disk verification layer of the storage operating system compares the updated disk topology and configuration with a set of rules associated with a particular file server configuration. If the disk topology or configuration is such that data loss or corruption can occur, the file server is halted. If the disk topology or configuration could be improved for higher availability an appropriate warning is issued to the user or administrator.

Abstract: A system and method for disk ownership in a network storage system. Each disk has two ownership attributes set to show that a particular file server owns the disk. In a preferred embodiment the first ownership attribute is the serial number of the file server being written to a specific location on each disk and the second ownership attribute is setting a SCSI-3 persistent reservation. In a system utilizing this disk ownership method, multiple file servers can read data from a given disk, but only the file server that owns a particular disk can write data to the disk.