Techniques for address mirroring of a file system journal are presented. A transactional file system update can correspond to a write operation to be performed at a first participant node of a data storage system. A journal transfer component can transfer the transactional file system update from an initiator node of the data storage system to a first journal associated with the first participant node and recovery information relating to the update to a second journal associated with a second participant node of the data storage system. The recovery information can be determined based on the update. To facilitate the update, a journal descriptor block can be generated and sent to the second participant node, such block comprising the recovery information, which can include transaction state, block addresses involved in the transaction, error correction-related information, or a mirror block address set for the block addresses where desired.

In one example, a method for writing data includes receiving a write request and performing a first type of logging process in connection with the write request, and creating a corresponding first logging record. Additionally, a second type of logging process is performed in connection with the write request, and a corresponding second logging record created, where the second type of logging process is different from the first type of logging process. Next, a determination is made, as between the two logging records, which of the logging records requires the least amount of non-volatile random access memory (NVRAM), and the logging record that requires the least amount of NVRAM is written to the NVRAM.

A primary storage system is equipped with a local storage subsystem having a mirror volume of a volume in a primary storage subsystem, and a remote storage subsystem having a mirror volume of the volume in the primary storage subsystem at a secondary site. When storing a write data from a host to a volume, the primary storage subsystem determines an SEQ# to be stored in a journal corresponding to the write request, creates a journal including the relevant SEQ# and a replica of the write data, and transmits the relevant SEQ# to the local storage subsystem, which creates a journal including the relevant SEQ# and stores it in its own journal volume. But when creation of the journal including the relevant SEQ# is stopped, the local storage subsystem creates a dummy journal including the relevant SEQ# but not including the write data.

Methods and systems are provided for improving a journaling file system by reducing journaling overhead utilizing a remapping interface to log-structured cloud block devices such that blocks in a journaling transaction are atomically mapped to their final disk locations with minimum overhead. With log-structured cloud block devices, all blocks may be stored in logfiles and indexed for access. By modifying the index of the destination block to point to the corresponding journal block, the additional write may be avoided, and a journal block may effectively be remapped from its original LBA to its destination LBA without any actual data movement, thereby reducing the file system journaling overhead.

Systems and methods for indexing and searching an event log to determine whether an object of a file system is current. An example method may comprise: arranging a plurality of events into multiple segments, the plurality of events comprising operations affecting a plurality of objects; generating multiple indexes in view of the one or more segments, the indexes comprising a composite index representing the plurality of objects modified by the plurality of events; and inspecting the composite index to determine an object of the plurality of objects is modified by at least one of the plurality of events.

Systems and methods for mirroring a file system journal are described herein. A method as described herein can include receiving, by a system operatively coupled to a processor, transactional file system updates corresponding to a write operation to be performed at a first node of the system; transferring, by the system, the transactional file system updates from an initiator node of the system to a first journal at the first node and a second journal at a second node of the system that is logically distinct from the first node and the initiator node; and committing, by the system, the transactional file system updates to the first journal and the second journal.

A method of managing data of a file system includes: obtaining information of an unallocated inode that is not currently used because a corresponding file has been deleted based on status of use of inodes stored in an inode bitmap and deletion information of the inodes stored in an inode table; retrieving a backup inode corresponding to the unallocated inode in a journal log area using the obtained information of the unallocated inode; and requesting selection of whether to permanently delete files corresponding to the retrieved backup inode.

A method, non-transitory computer readable medium and storage server computing device that allocates monotonically increasing sequence numbers to storage operations based on an order of the storage operations corresponding entries in a log. The storage operations are sequenced including by identifying a subset of the storage operations that are parallelizable. A file system data structure is allocated and populated with data associated with one of the storage operations. A determination is made when a rollback is detected based on whether a replay ledger index field of the file system data structure comprises one of the sequence numbers that is greater than another one of the sequence number corresponding to the one of the storage operations. The another one of the sequence numbers is inserted into the replay ledger index field, when the determining indicates that a rollback is not detected.

The present invention is directed to a method and system for efficient write journal entry management maintaining minimum write journal information stored in a nonvolatile memory through utilizing an additional structure in a fast volatile memory. The method and system may manage write journaling of a file volume including multiple fixed sized regions and assign a persistent 1-bit synchronization status (the write journal information) to each data region. In addition, a non-persistent I/O counter (the additional structure) for each region to manage the persistent 1-bit synchronization status during run-time. The present invention may provide a mechanism to determine when write I/O operations have not successfully completed to a specific region of the file volume.

Embodiments are directed to managing file systems. Update information associated with a change of a metric associated with a target object may be provided. A journal that includes a base bin that includes base records that associate the metric with each object in the file system. Records that include the change of the metric associated with the ancestors of target object may be generated. Another record that includes the change of the metric associated with the target object may be generated. A level bin associated with the base bin of the journal may be provided based on the update information. The records may be stored in the level bin using a sort order based on the ordering of the base bin records. In response a query, the journal may be employed to reduce latency in generating query results.