Abstract: Various information about storage resources in a UNIX or UNIX derivative operating system computing environment is gathered from various sources in response to scan requests. Where a given type of information for a given storage resource is gathered from multiple sources, the information is verified for consistency, and placed in a single file in an industry standard hierarchical format. Scan threads are timed to provide reliable performance.

Abstract: A first snapshot is taken of a first block storage resource that is initially identical in content to a second block storage resource. A second snapshot of the first block storage resource is taken at a later time. A record is kept of all blocks modified on the first block storage resource. Only those blocks modified between the time of the first and second snapshots are written to the second block storage resource. After all the modified blocks are written to the second block storage resource, a snapshot is taken of the second block storage resource to maintain a consistent snapshot of the second block storage resource in case of communication failure during the next round. The first snapshot is then deleted, the second takes the role of the first, and the next round of replication begins.

Abstract: A configuration of a first storage resource is written to a first instance of a single file in a standard hierarchical format that is stored locally in nonvolatile memory and updatable by the first resource. A configuration of a second storage resource is written to a second instance of the single file in the standard hierarchical format stored locally in nonvolatile memory and updatable by the second resource. The first instance and second instance of the single file are updated so that all configurations are present and identical in all instances of the single file.

Abstract: SCSI commands are used over IP (iSCSI) to trigger digest calculations of block span ranges. The parameters of the digest-calculation command include the command itself a block range, and the digest-calculation method to be used. A related combined command compares the digest-calculation result with a preexisting digest-calculation result. The parameters of the combined command include the parameters of the digest-calculation command, and the preexisting digest calculation result. Another command initializes a block range.

Abstract: A session-level cache provides space to reuse a task object and associated memory resources for a new request. Any additional resources necessary for the task are allocated by the system memory allocator.

Abstract: A network storage appliance having a main computing unit is provided with an embedded microcomputer for monitoring startup and operation of the main computing unit. The microcomputer has the ability to restart, power down or power up the main computing unit if any corresponding predetermined conditions exist. Local nonvolatile storage holds the firmware for the main computing unit and configuration for the appliance. After loading the firmware and configuration to the main computing unit, the nonvolatile storage is electronically disconnected from the main computing unit. Where two such appliances are coupled for redundancy between the same network storage and the network, the embedded microcomputers are separately coupled for communication to allow for negotiating a restart of one of the main computing units under the direction of the other, or if any predetermined conditions occur.

Abstract: The portion of a source block storage resource to be replicated, and the corresponding portion of the block storage resource being written to, are each divided into a predefined number of equal-sized spans. A digest calculation is then generated for each span in a corresponding pair and compared. If the digests do not match, those spans are divided into still smaller spans, and digests are calculated and compare iteratively, to identify smaller areas of discrepancies and reduce the number of blocks that are actually written.

Abstract: A network storage appliance having a main computing unit is provided with an embedded microcomputer for monitoring startup and operation of the main computing unit. The microcomputer has the ability to restart, power down or power up the main computing unit if any corresponding predetermined conditions exist. Local nonvolatile storage holds the firmware for the main computing unit and configuration for the appliance. After loading the firmware and configuration to the main computing unit, the nonvolatile storage is electronically disconnected from the main computing unit. Where two such appliances are coupled for redundancy between the same network storage and the network, the embedded microcomputers are separately coupled for communication to allow for negotiating a restart of one of the main computing units under the direction of the other, or if any predetermined conditions occur.

Abstract: SCSI commands are used over IP (iSCSI) to trigger digest calculations of block span ranges. The parameters of the digest-calculation command include the command itself a block range, and the digest-calculation method to be used. A related combined command compares the digest-calculation result with a preexisting digest-calculation result. The parameters of the combined command include the parameters of the digest-calculation command, and the preexisting digest calculation result. Another command initializes a block range.

Abstract: A session-level cache provides space to reuse a task object and associated memory resources for a new request. Any additional resources necessary for the task are allocated by the system memory allocator.

Abstract: A configuration of a first storage resource is written to a first instance of a single file in a standard hierarchical format that is stored locally in nonvolatile memory and updatable by the first resource. A configuration of a second storage resource is written to a second instance of the single file in the standard hierarchical format stored locally in nonvolatile memory and updatable by the second resource. The first instance and second instance of the single file are updated so that all configurations are present and identical in all instances of the single file.

Abstract: A snapshot of the data of a block storage resource is taken and made available over a network via iSCSI. The snapshot can be either read-only or read-write.

Abstract: The portion of a source block storage resource to be replicated, and the corresponding portion of the block storage resource being written to, are each divided into a predefined number of equal-sized spans. A digest calculation is then generated for each span in a corresponding pair and compared. If the digests do not match, those spans are divided into still smaller spans, and digests are calculated and compare iteratively, to identify smaller areas of discrepancies and reduce the number of blocks that are actually written.

Abstract: Various information about storage resources in a UNIX or UNIX derivative operating system computing environment is gathered from various sources in response to scan requests. Where a given type of information for a given storage resource is gathered from multiple sources, the information is verified for consistency, and placed in a single file in an industry standard hierarchical format. Scan threads are timed to provide reliable performance.

Abstract: A first snapshot is taken of a first block storage resource that is initially identical in content to a second block storage resource. A second snapshot of the first block storage resource is taken at a later time. A record is kept of all blocks modified on the first block storage resource. Only those blocks modified between the time of the first and second snapshots are written to the second block storage resource. After all the modified blocks are written to the second block storage resource, a snapshot is taken of the second block storage resource to maintain a consistent snapshot of the second block storage resource in case of communication failure during the next round. The first snapshot is then deleted, the second takes the role of the first, and the next round of replication begins.