Abstract: Described are techniques for managing data locations of derived storage objects. The techniques include accessing a primary metadata tree providing a lookup path using a virtual address to locate data for a primary object in physical storage pointed to by a leaf node of the primary metadata tree and providing a sub-tree from a leaf node of the primary metadata tree associated with the primary object, the sub-tree providing lookup paths using virtual addresses for derived objects. Wherein a derived object is a view of the primary object at a specific point in time, with copy leaf nodes of the sub-tree pointing to stored data of the derived objects. The techniques further include maintaining an ancestry graph associated with the sub-tree with the ancestry graph linking derived object identifiers to provide an ancestral chain lookup to identify derived object identifiers of the closest stored physical data of a derived object.

Abstract: A computer-implemented method according to one aspect includes creating an initialization vector, utilizing an instance of plaintext and a secret key; encrypting the instance of plaintext, utilizing the initialization vector, the secret key, and the instance of plaintext; combining the initialization vector and the encrypted instance of plaintext to create a ciphertext string; and outputting the ciphertext string.

Abstract: A computer-implemented method according to one embodiment includes compressing an uncompressed instance of data to create a compressed instance of data; encrypting the compressed instance of data in response to determining that a size of the compressed instance of data is less than a predetermined threshold; creating a message authentication code (MAC) for the encrypted compressed instance of data; and adding a variable-length zero pad and the MAC to the encrypted compressed instance of data to create a formatted string.

Abstract: Described are techniques for managing data locations of derived storage objects. The techniques include accessing a primary metadata tree providing a lookup path using a virtual address to locate data for a primary object in physical storage pointed to by a leaf node of the primary metadata tree and providing a sub-tree from a leaf node of the primary metadata tree associated with the primary object, the sub-tree providing lookup paths using virtual addresses for derived objects. Wherein a derived object is a view of the primary object at a specific point in time, with copy leaf nodes of the sub-tree pointing to stored data of the derived objects. The techniques further include maintaining an ancestry graph associated with the sub-tree with the ancestry graph linking derived object identifiers to provide an ancestral chain lookup to identify derived object identifiers of the closest stored physical data of a derived object.

Abstract: A computer-implemented method according to one aspect includes creating an initialization vector, utilizing an instance of plaintext and a secret key; encrypting the instance of plaintext, utilizing the initialization vector, the secret key, and the instance of plaintext; combining the initialization vector and the encrypted instance of plaintext to create a ciphertext string; and outputting the ciphertext string.

Abstract: A computer-implemented method according to one aspect includes creating an initialization vector, utilizing an instance of plaintext and a secret key; encrypting the instance of plaintext, utilizing the initialization vector, the secret key, and the instance of plaintext; combining the initialization vector and the encrypted instance of plaintext to create a ciphertext string; and sending the ciphertext string to a storage device performing deduplication.

Abstract: A method, computer system, and a computer program product for calculating bandwidth requirements is provided. The present invention may include receiving a recovery point objective (RPO). The present invention may also include simulating, using a virtual disk, a set of inter-site data transfers between a first data storage controller and a second data storage controller, wherein the second data storage controller is modelled by the virtual disk. The present invention may then include collecting a set of data correlating to a set of bandwidth factors, based on the simulated set of inter-site data transfers. The present invention may further include calculating, using the virtual disk, a bandwidth required for data replication for disaster recovery, based, at least in part, on the set of bandwidth factors and the RPO.

Abstract: A computer-implemented method according to one embodiment includes compressing an uncompressed instance of data to create a compressed instance of data; encrypting the compressed instance of data in response to determining that a size of the compressed instance of data is less than a predetermined threshold; creating a message authentication code (MAC) for the encrypted compressed instance of data; and adding a variable-length zero pad and the MAC to the encrypted compressed instance of data to create a formatted string.

Abstract: A computer-implemented method according to one aspect includes creating an initialization vector, utilizing an instance of plaintext and a secret key; encrypting the instance of plaintext, utilizing the initialization vector, the secret key, and the instance of plaintext; combining the initialization vector and the encrypted instance of plaintext to create a ciphertext string; and sending the ciphertext string to a storage device performing deduplication.

Abstract: A data storage system comprises physical storage, cache memory and a processor connected to the physical storage and the cache memory. The processor is arranged to maintain a set of active regions in the cache memory, each active region having a size equal to an integer multiple of an update size of a flash chip within the physical storage, where the integer could be 1. The processor receives requests for one or more blocks of the cache memory from components within the storage system and allocates one or more blocks from an active region in response to a received request. If the processor determines that all blocks in an active region have been allocated and that all allocated blocks within this region have been written to, then the processor destages the content of this region to the physical storage.

Abstract: An apparatus for controlling a storage system having a data replication function, comprises: a storage array component being operable to send notification to a replication engine that a write of data to a primary storage location by a host is subject to data replication; the replication engine being operable to receive the notification and in response to instruct the storage array to copy the data to a secondary storage location; wherein the data is copied to the secondary storage location unmediated by the replication engine.

Abstract: A method, computer system, and a computer program product for calculating bandwidth requirements is provided. The present invention may include receiving a recovery point objective (RPO). The present invention may also include simulating, using a virtual disk, a set of inter-site data transfers between a first data storage controller and a second data storage controller, wherein the second data storage controller is modelled by the virtual disk. The present invention may then include collecting a set of data correlating to a set of bandwidth factors, based on the simulated set of inter-site data transfers. The present invention may further include calculating, using the virtual disk, a bandwidth required for data replication for disaster recovery, based, at least in part, on the set of bandwidth factors and the RPO.

Abstract: Determining the bandwidth required for data replication for disaster recovery. Given a specified recovery point objective (RPO), bandwidth requisitioning and usage is determined according to meet the RPO based on observed factors.

Abstract: A computer-implemented method for managing storage devices in a storage subsystem having an array of storage devices, according to one embodiment, includes determining that at least one storage device in the array of storage devices has failed. Storage device characteristics of the failed storage device are compared with storage device characteristics of each of a plurality of candidate devices, and an attempt is made to identify a first candidate storage device having storage device characteristics that match the storage device characteristics of the failed storage device. A second candidate storage device having storage device characteristics most similar to the storage device characteristics of the failed storage device is identified in response to not identifying a candidate device that matches the failed storage device.

Abstract: A data storage system comprises physical storage, cache memory and a processor connected to the physical storage and the cache memory. The processor is arranged to maintain a set of active regions in the cache memory, each active region having a size equal to an integer multiple of an update size of a flash chip within the physical storage, where the integer could be 1. The processor receives requests for one or more blocks of the cache memory from components within the storage system and allocates one or more blocks from an active region in response to a received request. If the processor determines that all blocks in an active region have been allocated and that all allocated blocks within this region have been written to, then the processor destages the content of this region to the physical storage.

Abstract: A method of managing a data storage cache, comprising: providing a redundant cache comprising first and second caches associated with first and second storage volumes. One of the first and second storage volumes is an active, and one is a passive volume. A write request is received at one of the volumes. If the write request is received at the passive volume, it is forwarded to the active volume. It is determined whether the active volume is a low latency volume. If it is a low latency volume, it is determined whether data exists in the cache associated with the active volume which overlaps with data contained in the write request. If no data exists in that cache which overlaps with data contained in the write request, the write request is processed straight down to said active volume.

Abstract: Systems for transmitting an application message between nodes of a clustered data processing system are disclosed. One system includes a determination of whether one or more application messages may currently be transmitted to a first node of a plurality of nodes from a second node of the plurality of nodes. The system further includes processing the one or more application messages in response to a determination that the one or more application messages may be currently transmitted.

Abstract: A method and system are provided for storage checkpointing in a mirrored virtual machine system. The method includes a storage controller receiving a modifying operation to storage from a virtual machine and carrying out the modifying operation in a non-destructive manner by saving the modifying operation data to a checkpointing region of storage and preserving the stored previous data state. The method also includes receiving a checkpoint notification and committing modifying operation data from the checkpointing region and releasing the stored previous data state. If a failover notification is received, the storage controller rolls back the physical storage to match a checkpoint state.

Abstract: A method and system are provided for storage checkpointing in a mirrored virtual machine system. The method includes a storage controller receiving a modifying operation to storage from a virtual machine and carrying out the modifying operation in a non-destructive manner by saving the modifying operation data to a checkpointing region of storage and preserving the stored previous data state. The method also includes receiving a checkpoint notification and committing modifying operation data from the checkpointing region and releasing the stored previous data state. If a failover notification is received, the storage controller rolls back the physical storage to match a checkpoint state.

Abstract: A method of managing a data storage cache, comprising: providing a redundant cache comprising first and second caches associated with first and second storage volumes. One of the first and second storage volumes is an active, and one is a passive volume. A write request is received at one of the volumes. If the write request is received at the passive volume, it is forwarded to the active volume. It is determined whether the active volume is a low latency volume. If it is a low latency volume, it is determined whether data exists in the cache associated with the active volume which overlaps with data contained in the write request. If no data exists in that cache which overlaps with data contained in the write request, the write request is processed straight down to said active volume.