Abstract: A method, system, and program product for controlling multi-node access to a disk storage system. In accordance with the method of the present invention, an active access authorization is set for a first node. The active access authorization enables read and write access by the first node to user and meta data within the disk storage system. A passive access authorization is set for a second node. The passive access authorization enables read-only access by the second node to logical volume management meta data within the disk storage system.

Abstract: A method, system and apparatus for allowing a mirroring map to be used with more than one piece of data are provided. First, a mirroring map is created and given a name. Then, the name of the mirroring map and the mirroring map itself are stored into the computer system. When a piece of data is to be stored in accordance with the mirroring map any time thereafter, the name of the mirroring map is used to associate the mirroring map with the piece of data.

Abstract: A method, system, apparatus and computer program product for reducing the number of physical storage systems needed for a volume group to remain active are provided. This is accomplished by creating mirroring sets out of the physical storage systems in the volume group and by setting up a policy that so long as one mirror out of each mirror set is available, the volume group should be allowed to remain active. To activate a volume group (i.e., when the computer system is turned or reset), there have to be at least one full mirror set and at least one mirror out of each remaining mirror set available. These two policies guarantee that there will always be valid metadata in the system.

Abstract: A system and method for recovering from a failure in a clustered environment sharing a common nonvolatile storage device. The first computer reserves the device by identifying itself in a reservation key associated with the device. The first device sends a signal to one or more backup computers informing the backup computers that the first computer is operational. When the first computer fails to operate, one of the backup computers breaks the first computer's reservation to the storage device and writes a new reservation key to the reservation storage area identifying the backup computer as the reservation holder of the storage device. When the first computer is reinitialized, it reads the reservation storage area and does not attempt to break the reservation made by the backup computer. One embodiment provides for the first computer to request control from the backup computer upon being reinitialized whereupon the backup computer releases its reservation and relinquishes control.

Abstract: A method, system, and program product for controlling multi-node access to a disk storage system. In accordance with the method of the present invention, an active access authorization is set for a first node. The active access authorization enables read and write access by the first node to user and meta data within the disk storage system. A passive access authorization is set for a second node. The passive access authorization enables read-only access by the second node to logical volume management meta data within the disk storage system.

Abstract: A method, system and apparatus for reducing the number of physical storage systems needed for a volume group to remain active are provided. This is accomplished by creating mirroring sets out of the physical storage systems in the volume group and by setting up a policy that so long as one mirror out of each mirror set is available, the volume group should remain active. To activate a volume group (i.e., when the computer system is turned or reset), there have to be at least one full mirror set and at least one mirror out of each remaining mirror set available. These two policies guarantee that there will always be valid metadata in the system.

Abstract: A method, system and apparatus for allowing a mirroring map to be used with more than one piece of data are provided. First, a mirroring map is created and given a name. Then, the name of the mirroring map and the mirroring map itself are stored into the computer system. When a piece of data is to be stored in accordance with the mirroring map any time thereafter, the name of the mirroring map is used to associate the mirroring map with the piece of data.

Abstract: A method and system for automatically performing one or more operations on multiple computer systems within a cluster are disclosed. In accordance with the present invention, a begin operations command construct is defined within an input file. In addition, an input command indicating one or more operations to be performed on at least two computer systems within the cluster and an end operations command construct are defined. In response to a selected input, one or more operations indicated by the input command are automatically performed on at least two computer systems. In accordance with one embodiment, the begin operations command construct indicates selected computer systems within the cluster on which the one or more operations are to be performed and whether the operations are to be performed on the selected computer systems serially or in parallel.

Abstract: A method and system for dynamically reconfiguring a cluster of computer systems are disclosed. In accordance with the present invention, a first configuration file is provided at a plurality of computer systems within a cluster that specifies a current configuration of the cluster. A second configuration file is created at each of the plurality of computer systems that specifies a modified configuration of the cluster. The modified configuration is then verified. In response to the verification, the cluster is operated utilizing the modified configuration. In accordance with one embodiment, the dynamic reconfiguration of the cluster can include a reconfiguration of the cluster topology or resources.

Abstract: A method for serializing access to computer system resources without disabling interrupts in critical code sections or requiring excessive use of spin locks. A queue lock is introduced that allows an interrupt process to enqueue and be processed in turn without a spin lock and to block process code access to a particular resource until all interrupts are processed. Process level code is blocked from accessing a locked resource while requests for accesses from interrupt level code are queued in a deferred work queue which is processed prior to the release of the blocking lock. Establishment of deferred work queue means that processing can continue without disablement of interrupts and without significant overhead consumed by processes holding spin locks.