Vmware, Inc.

Hardik Singh Negi

Wenguang Wang

Junlong Gao

Eric Shannon Knauft

Vamsi Gunturu

Jiaqi Zuo

Enning Xiang

Pranay Singh

Petr Vandrovec

A method for efficient write-back for journal truncation is provided. A method includes maintaining a journal in a memory of a computing system including a plurality of records. Each record indicates a transaction associated with one or more pages in an ordered data structure and maintaining a dirty list including an entry for each page indicated by a record in the journal. Each entry in the dirty list includes a respective first log sequence number (LSN) associated with a least recent record of the plurality of records that indicates the page and a respective second LSN associated with a most recent record of the plurality of records that indicates the page. The method includes determining to truncate the journal. The method includes identifying one or more records, of the plurality of records, from the journal to write back to a disk, where the identifying is based on the dirty list.

Efficient write-back for journal truncation

A method for efficient journal truncation is provided. A method for journal truncation includes maintaining a journal in a memory of a computing system including a plurality of records. Each record indicates a transaction in an ordered data structure. The method includes maintaining a truncation queue in the memory including one or more entries. Each entry in the truncation queue includes a physical on-disk offset associated with a different record of the plurality of records. The method includes determining to truncate the journal and truncating records, of the plurality of records, from the journal starting from a beginning record in the journal up to the record with the physical on-disk offset associated a least recent entry of the one or more entries in the truncation queue, where the truncating includes removing the records from the memory.

Efficient incremental journal truncation policy

A method for modifying key-value pairs of a B+ tree is provided. The method receives a request to modify a particular key-value pair. Each node of the tree has a modification number. The method traverses a path on the tree from the root node toward the particular node. The traversing includes upon reaching a parent node of the path, acquiring a shared lock on both the parent node and a child node one level below the parent node. Upon determining that the child node is the particular node, the method stores the modification number of the particular node, releases the shared lock on the particular node, compares a current modification number of the node with its stored number, and acquires an exclusive lock on the node if the numbers are the same. The method increments the current modification number of the node and modifies it while in the exclusive lock.

Enhanced locking mechanism for B+ tree data structures

A method for resumeable snapshot deletion is provided. A method for deletion of nodes maintained in an ordered data structure for a first snapshot includes processing the nodes maintained in the ordered data structure according to a defined order, setting a node path cursor with a pointer to a node and an indication of the deletion of the node; storing the node path cursor in a persistent storage; and during processing of the nodes: detecting a failure; after the failure, checking the pointer of the node path cursor; and resuming processing of the nodes starting from the first node indicated by the pointer.

Resumable copy-on-write (COW) B+tree pages deletion

A method for cleaning an object storage having a plurality of segments is provided. Each segment includes an identifier through which the segment is accessed. The method identifies a first segment in the plurality of segments. The first segment includes a first identifier and a first size. The method determines that a utilization ratio for the first segment is below a threshold. As a result, the method generates a second segment from the first segment, such that the second segment includes a second identifier that is the same as the first identifier and a second size that is smaller than the first size. The method then writes the second segment to the object storage.

Shrinking segment cleaning algorithm in an object storage

System and method for managing snapshots of storage objects in a storage system use a consolidation operation to reduce read amplification for stored snapshots of a storage object that are stored in log segments in the storage system according to a log-structured file system as storage service objects. The consolidation operation involves identifying target log segments among the log segments that include live blocks that are associated with the latest snapshot of the storage object and determining the number of the live blocks included in each of the target log segments. Based on the number of the live blocks in each of the target log segments, candidate consolidation log segments are determined from the target log segments. The live blocks in the candidate consolidation log segments are then consolidated to new log segments, which are uploaded to the storage system as new storage service objects.

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Sunnyvale, CA, United States of America

Hardik Singh Negi