Abstract: A method and apparatus for identifying ownership by a computer of a storage device connected to a computer network is described. A first ownership information is written into a selected sector of the storage device by a computer having ownership of the device as a first indicia of ownership. A second ownership information is written into a storage device label of the storage device by the computer having ownership as a second indicia of ownership, the storage device label visible to a plurality of computers connected to the computer network. In the event that at a future time the first indicia of ownership does not match the second indicia of ownership, the first indicia of ownership is taken as definitive of ownership of the storage device.

Abstract: A data storage system has two computers. Each computer is assigned to a set of data. Two copies of each set of data are maintained. A first copy is stored on a first set of disks and a second copy is stored on a second set of disks. Each time that a data is written by a computer, a label is written to each set of disks, the label having fields for a status of each computer, a first ordinal which is increased each time that a new data is written, and a time stamp giving a time at which the last write was performed. After failure of a computer, a processor determines, in response to reading the labels of the first set of disks and the second set of disks, the most up to date copy of the data assigned to the failed computer.

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: A method for managing a plurality of servers is disclosed. Each server of the plurality of servers has access to data stored by other servers. The data is stored to one or more data storage devices. Coordinating information is written for the plurality of servers to a master mailbox record. The coordinating information includes data that each server uses to recover after a failure by a server. The master mailbox record is stored on a selected storage device at a location known to the plurality of servers, and the selected storage device is designated as a lock storage device. A plurality of lock storage devices is chosen so that in the event of failure of a server of the plurality of servers, at least one lock storage device will be available to the remaining servers.

Abstract: A system is provided to improve storage server performance. The system comprises a receiving component of a storage server to receive a partner server's file system metadata while the partner server operates in a normal mode. The partner server's file system metadata is stored in the storage servers metadata cache and is used to mount the partner server's file system when the first server transitions into a takeover mode of operation.

Abstract: In a method for operating a data storage system, a request is issued that an ownership attribute of a logical arrangement of storage space associated with a first storage system be associated with a second storage system. In response to the request, the ownership attribute is changed to a state of unowned. In response to the request, and in response to the state of unowned, the ownership attribute of the logical arrangement of storage space is changed to a new set of attributes associated with the second storage system to change ownership of the logical arrangement of storage space from the first storage system to the second storage system.

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 clustered storage server detects an offline condition in another storage server in the cluster and executes a cluster takeover procedure which includes taking control of the storage system associated with the offline storage server, and merging a local control-of-service policy with a control-of-service policy associated with the offline storage server.

Abstract: A method for managing a cluster of file servers is disclosed. The method has the first step of writing coordinating information for a plurality of servers of the cluster of servers to a master mailbox record, the master mailbox record written to a specific location on each disk of a set of lock disks, the set of lock disks having a plurality of disks, the plurality of disks chosen so that in the event of failure of a server of the plurality of servers, at least one lock disk will be available to the remaining servers. The method has the second step of writing a second copy of eth coordinating information to the master mailbox record of the set of lock disks.

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.

Abstract: A data storage system has two computers. Each computer is assigned to a set of data. Two copies of each set of data are maintained. A first copy is stored on a first set of disks and a second copy is stored on a second set of disks. Each time that a data is written by a computer, a label is written to each set of disks, the label having fields for a status of each computer, a first ordinal which is increased each time that a new data is written, and a time stamp giving a time at which the last write was performed. After failure of a computer, a processor determines, in response to reading the labels of the first set of disks and the second set of disks, the most up to date copy of the data assigned to the failed computer.

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 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: 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 for an improved mailbox mechanism to contain coordinating information for computers in a cluster environment is provided. The system and method creates two copies of a master mailbox record stored in a set and predetermined location on disks associated with the cluster. A subset of the disks is designated as lock disks, which must contain the most up-to-date coordinating information.

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 system and method for fast (“warm”) reboot of a file server is provided, which skips certain conventional boot processes when circumstances warrant, in order to reduce server downtime. In particular, time is saved by avoiding a full shutdown of the processor and memory, and by causing the firmware to refrain from a full clearance of the file server memory. Instead, the firmware accesses a retained copy of the storage operating system kernel from a reserved location in the file server memory so that an operative version of the kernel is reestablished at the appropriate address space in memory without requiring a time-consuming read of the kernel image from disk. In addition, other “normal” (cold) reboot operations such as full memory tests, hardware checks and memory zeroing are avoided as appropriate—saving further time in the overall reboot process, while still attaining the desired reinitialization of key applications and functions.

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.