Abstract:
A system and method for enabling parallel replay of a backup memory log of client transaction request entries to a network storage appliance file system is provided. The backup memory is typically implemented as a non-volatile random access memory (NVRAM). An initiator establishes a swarm of messages with a plurality of transaction blocks pointing to logged request entries and related states associated therewith. The states represent the various phases of file system recovery and disk storage including a retrieval of disk information (data and meta-data), typically in the form of a LOAD, and a subsequent modify phase. The swarm is transferred to the file system for parallel disk information-retrieval in an interleaved process. Any transactions that cannot be performed due to a required prerequisite action (e.g. a prior file-create) are returned to the initiator for reloading once the prerequisite action has occurred.
Abstract:
A method and apparatus for operating a data storage system is disclosed. An original active file system holds incoming write transactions. Data is written at a selected time to blocks in a data storage device of the original active file system, the data written to blocks which do not hold old data of the data storage system. Pointers to data of the original active file system are written at the selected time to the data storage device, the pointers written to blocks which do not hold old data of the data storage system, the pointers and a previously saved data of the active file system forming a consistency point of the original active file system at the selected time. A new active file system is started using the consistency point of the original active file system at the selected time.
Abstract:
The invention provides an improved method and apparatus for creating a snapshot of a file system. A “copy-on-write” mechanism is used. The snapshot uses the same blocks as the active file system until the active file system is modified. Whenever a modification occurs, the modified data is copied to a new block and the old data is saved. In this way, the snapshot only uses space where it differs from the active file system, and the amount of work required to create the snapshot is small. A record of which blocks are being used by the snapshot is included in the snapshot itself, allowing effectively instantaneous snapshot creation and deletion. A snapshot can also be deleted instantaneously simply by discarding its root inode.
Abstract:
Maintenance of plural active file systems, wherein each of the active file systems initially access data shared with another of the active file systems, and wherein changes made to each of the active file systems are not reflected in other active file systems. When a second active file system is created based on a first active file system, the first active file system and the second active file system initially share data. When changes are made to the first active file system, modified data is recorded in the first active file system in a location that is not shared with the second active file system. When changes are made to the second active file system, modified data is recorded in the second active file system in a location that is not shared with the first active file system. Also, creation of the plural active file systems.
Abstract:
A file system layout apportions an underlying physical volume into one or more virtual volumes (vvols) of a storage system. The underlying physical volume is an aggregate comprising one or more groups of disks, such as RAID groups, of the storage system. The aggregate has its own physical volume block number (pvbn) space and maintains metadata, such as block allocation structures, within that pvbn space. Each vvol has its own virtual volume block number (vvbn) space and maintains metadata, such as block allocation structures, within that vvbn space. Notably, the block allocation structures of a vvol are sized to the vvol, and not to the underlying aggregate, to thereby allow operations that manage data served by the storage system (e.g., snapshot operations) to efficiently work over the vvols. The file system layout extends the file system layout of a conventional write anywhere file layout system implementation, yet maintains performance properties of the conventional implementation.
Abstract:
A file system determines the relative vacancy of a collection of storage blocks, i.e., an “allocation area”. This is accomplished by recording an array of numbers, each of which describes the vacancy of a collection of storage blocks. The file system examines these numbers when attempting to record file blocks in relatively contiguous areas on a storage medium, such as a disk. When a request to write to disk occurs, the system determines the average vacancy of all of the allocation areas and queries the allocation areas for individual vacancy rates. The system preferably writes file blocks to the allocation areas that are above a threshold related to the average storage block vacancy of the file system.
Abstract:
Maintenance of plural active file systems, wherein each of the active file systems initially access data shared with another of the active file systems, and wherein changes made to each of the active file systems are not reflected in other active file systems. When a second active file system is created based on a first active file system, the first active file system and the second active file system initially share data. When changes are made to the first active file system, modified data is recorded in the first active file system in a location that is not shared with the second active file system. When changes are made to the second active file system, modified data is recorded in the second active file system in a location that is not shared with the first active file system. Also, creation of the plural active file systems.
Abstract:
The invention provides a method and system for improving data access of a reliable file system. In a first aspect of the invention, the file system determines the relative vacancy of a collection of storage blocks, herein called an “allocation area”. This is accomplished by recording an array of binary numbers. Each binary number in the array describes the vacancy of a collection of storage blocks. The file system examines these binary numbers when attempting to record file blocks in relatively contiguous areas on a storage medium, such as a hard disk. When a request to write to disk occurs, the system determines the average vacancy of all the allocation areas and queries the allocation areas for individual vacancy rates such as sequentially. The system preferably writes file blocks to the allocation areas that are above a threshold related to the average storage block vacancy of the file system. If the file in the request to write is larger than the selected allocation area, the next allocation area above the threshold is preferably used to write the remaining blocks of the file.
Abstract:
Maintenance of plural active file systems, wherein each of the active file systems initially access data shared with another of the active file systems, and wherein changes made to each of the active file systems are not reflected in other active file systems. When a second active file system is created based on a first active file system, the first active file system and the second active file system initially share data. When changes are made to the first active file system, modified data is recorded in the first active file system in a location that is not shared with the second active file system. When changes are made to the second active file system, modified data is recorded in the second active file system in a location that is not shared with the first active file system. Also, creation of the plural active file systems.
Abstract:
A technique to name data is disclosed to allow preservation of storage efficiency over a link between a source and a destination in a replication relationship as well as in storage at the destination. The technique allows the source to send named data to the destination once and refer to it by name multiple times in the future, without having to resend the data. The technique also allows the transmission of data extents to be decoupled from the logical containers that refer to the data extents. Additionally, the technique allows a replication system to accommodate different extent sizes between replication source and destination while preserving storage efficiency.