Netapp, Inc.

Boaz Harrosh

Amit Golander

Sagi Manole

Yigal Korman

Omer Caspi

A data structure used in memory-based file system, method and apparatus using thereof. The data structure comprising: a tree of the nodes comprising tree nodes and leaf nodes, each tree node points to at least one node, each leaf node is associated with a plurality of data unit elements each of which representing a data unit, wherein each data unit element is associated with two pointers, wherein at least one of the two pointers is capable of pointing to a data unit or to a data unit element; and a cyclic linked list of data unit elements representing identical clones of a data unit, wherein the cyclic linked list comprises a first element pointing directly to the data unit, wherein from each element in the cyclic linked list, the data unit can be reached in time complexity of O(1).

Data unit cloning in memory-based file systems

A method, apparatus and product for accelerating concurrent access to a file in a memory-based file system. The method comprising receiving a request issued by a program, for accessing a file stored in a memory-based file system; and subject to the request being associated with data modification of data within the file, and subject to the modification not necessitating change in a structure of a data structure used for content lookup for the file, acquiring a lock to the file to the program, wherein the lock is acquired in a shared mode.

Accelerating concurrent access to a file in a memory-based file system

Logical mirroring of an initiator server running a memory aware file system to a multi-tiered target server by receiving at a first tier of the target server data that was modified at the initiator server and retaining at the first tier of the target server a first subset of the data and moving to a second tier of the target server a second subset of the data to efficiently utilize the multi-tiered target server.

Method and apparatus for logical mirroring to a multi-tier target node

A persistent memory based distributed-journal file system, comprising:

Persistent memory based distributed-journal file system

Method, apparatus and product for data cloning in a memory-based file systems. A content of each object of the file system is retained in data units and represented using a tree of the nodes comprising tree nodes and leaf nodes. The file system utilizes a volatile resource usage collection and volatile reference counters for each node of the nodes. In response to mounting the file system, a storage retaining a file system metadata is scanned to compile the volatile resource usage collection and the volatile reference counters. In response to a determination to reuse a pointed node of a tree of an object by a pointing node, a volatile reference counter of the pointed node is updated and the pointing node is atomically set, using a single instruction, to point to the pointed node.

Data cloning in memory-based file systems

Method, system and product for direct access to de-duplicated data units in memory-based file systems. The method comprising: updating a page entry in a page table of a process to include a direct access pointer to a de-duplicated data unit retained by the memory-based file system, wherein the page entry is set to be write protected; detecting a page fault occurring due to the process performing a store instruction to the de-duplicated data unit; and in response to said detecting: allocating a new data unit; copying content of the de-duplicated data unit to the new data unit; and replacing the direct access pointer to the de-duplicated data unit with a direct access pointer to the new data unit.

Direct access to de-duplicated data units in memory-based file systems

A computer implemented method for updating a file system tree structure through an atomic operation, comprising one or more hardware processor adapted for designating a file system comprising a plurality of files arranged in a plurality of tree structures, the file system is based on a direct mapping persistent memory, receiving instructions from a client to alter an altered file of the plurality of files, creating an alternate tree structure to apply the alteration in case the alteration involves a non-atomic tree structure operation to an original tree structure of the plurality of tree structures containing the altered file and committing the alteration to the file system through an atomic operation.

Atomic update of B-tree in a persistent memory-based file system

Managing pages in a memory based file system by maintaining a memory into two lists, an Lr list and an Lf list, moving pages from the Lr list to the Lf list based on a repeated access pattern, and moving a page out of the Lr list or the Lf list arbitrarily, thereby enabling the two lists to re-grow according to current workload.

Method and apparatus for adaptively managing data in a memory based file system

Methods for data placement in a memory-based file system are described, including copying a user data unit from a second storage type device to a first storage type device based on an access request to the file system, the first storage type device being a faster access device than the second storage type device, referencing the user data unit in the first storage type device by a byte addressable memory pointer, and using the byte addressable memory pointer to copy the user data unit from the first storage type device to the second storage type device based on data access pattern.

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Tel Aviv, Israel

Boaz Harrosh