Browse Definitions:
Definition

OpLock (opportunistic lock)

Contributor(s): Matthew Haughn

Opportunistic lock (OpLock) is a form of file locking used to facilitate caching and access control and improve performance.

OpLocks are made to enable simultaneous file access by multiple users while also improving performance for synchronized caches. In a synchronized cache, when a client requests a file from a server, the shared file may be cached to avoid subsequent trips over the network to retrieve it.

OpLock is part of the Server message block (SMB) protocol, also known as the Common Internet File System (CIFS) protocol.  OpLocks include batch locks, exclusive locks and level 2 OpLocks.

Batch locks are used where frequent open and close requests can be paired; the system ignores unnecessary close requests if the file is to be reopened, thus reducing the performance impact of the requests.

Exclusive locks are used when a client is the only entity or process that has the file open. In that case, all changes are cached before sending the file back to the server.

Level 2 OpLocks come into effect when an OpLock held by a client is opened by a third party, substituting the client’s former exclusive lock.

An OpLock is not a command but a request typically sent from client to server and fulfilled under allowable conditions or the particular opportunity for which it is named. When a lock is no longer valid a break is sent to the client to end it.

There are some implications that OpLocks can cause corruption and performance issues in ISAM  (Indexed Sequential Access Method) databases. As a result, some companies – Symantec among them -- have recommended disabling OpLocks as a best practice.

This was last updated in May 2015

Continue Reading About OpLock (opportunistic lock)

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • risk map (risk heat map)

    A risk map, also known as a risk heat map, is a data visualization tool for communicating specific risks an organization faces.

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...

SearchSecurity

  • FIDO (Fast Identity Online)

    FIDO (Fast ID Online) is a set of technology-agnostic security specifications for strong authentication. FIDO is developed by the...

  • cryptanalysis

    Cryptanalysis is the study of ciphertext, ciphers and cryptosystems with the aim of understanding how they work and finding and ...

  • Trojan horse (computing)

    In computing, a Trojan horse is a program that appears harmless, but is, in fact, malicious.

SearchHealthIT

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

SearchStorage

  • cloud storage provider

    A cloud storage provider, also known as a managed service provider (MSP), is a company that offers organizations and individuals ...

  • personal cloud storage (PCS)

    Personal cloud storage (PCS) enables users to store data, photos, music, videos and other files on a local network-attached ...

  • cloud SLA (cloud service-level agreement)

    A cloud SLA (cloud service-level agreement) is an agreement between a cloud service provider and a customer that ensures a ...

SearchSolidStateStorage

  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.

Close