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Sprache English
Stufe Universität
Erstellt / Aktualisiert 28.11.2020 / 17.07.2021
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0 Exakte Antworten 72 Text Antworten 0 Multiple Choice Antworten
Fenster schliessen

Advantages and Disadvantages of synchronous replication?

  • Advantages

    • No inconsistencies (identical copies)

    • Regarding the local copy yields the most up-to-date value

    • Changes are atomic

  • Disadvantages

    • An operation has to update all sites

      • Linger execution time

      • Worse response time

      • Poor availability

Fenster schliessen

Advantages and Disadvantages of asynchronous replication?

  • Advantages

    • An operation is always local

      • Good response time

      • High availability

  • Disadvantages

    • Data inconsistencies

    • A local read does not always return the most up-to-date value

    • Changes to all copies are not guaranteed

    • Replication is not transparent

Fenster schliessen

Advantages and Disadvantages of update everywhere replication?

  • Advantages

    • Any site can run an operation

    • Load is evenly distributed

  • Disadvantages

    • Copies must be synchronized

    • Concurrent updates will cause conflicts

Fenster schliessen

Advantages and Disadvantages of primary copy replication?

  • Advantages

    • No inter-site synchronization

    • There is always one site that has all the updates

  • Disadvantages

    • The load at the primary copy can be quite large

    • Reading the local copy may not yield the most up-to-date value

Fenster schliessen

Synchronous + Primary copy

Advantages/Disadvantages?

Practical?

  • Advantages

    • Updates do not need to be coordinated

    • No inconsistencies

  • Disadvantages

    • Longest response time

    • Only useful with few updates

    • Local copies are read-only

    • Low availability

  • Ideal: Globally correct, Remote writes

  • Practical: Too expensive (usefulness)

Fenster schliessen

Asynchronous + Primary copy

Advantages/Disadvantages?

Practical?

  • Advantages

    • No coordination necessary

    • Short response times

  • Disadvantages

    • Local copes are not up-to-date

    • Inconsistencies

    • Low write availability

  • Ideal: Inconsistency reads

  • Practical: Feasible (limited scalability)

Fenster schliessen

Synchronous + Update everywhere

Advantages/Disadvantages?

Practical?

  • Advantages

    • No inconsistencies

    • Elegant symmetric solution

  • Disadvantages

    • Long response times

    • Updates need to be coordinated

    • Low availability

  • Ideal: Globally correct, Local writes

  • Practical: Too expensive (does not scale)

Fenster schliessen

Asynchronous + Update everywhere

Advantages/Disadvantages?

Practical?

  • Advantages

    • No centralized coordination

    • Shortest response times

    • High availability

  • Disadvantages

    • Inconsistencies and conflicts

    • Updates can be lost (reconciliation)

  • Ideal: Inconsistency reads, Reconciliation

  • Practical: Feasible in many applications