ZRS - ZODB Replicated Storage

Zope Object DataBase (ZODB) is a persistent object-oriented database for Python objects. It is default Plone data storage and part of the Zope web application server, but can also be used independently, clustered over network or over another database engine.
ZODB features:

  • pluggable storage interface,
  • built-in caching,
  • rich transaction support,
  • history/undo,
  • multiversion concurrency control (MVCC).

ZRS - for Plone and even more

ZODB replicated storage (ZRS) supplies database replication for ZODB. Each database can have a primary storage and any number of secondary storages that automatically synchronizes data with the primary storage. ZRS had been a commercial software developed by Zope Corporation, but since May 2013 it was released as an open source solution: pypi.python.org/pypi/zc.zrs.

ZRS features:

  • Primary->secondary replication.
  • The primary storage server is a read-write storage.
  • The secondary storage is read-only.
  • ZRS improves scalability as secondary storage can be used by read-only application clients to reduce server load.
  • Administrators can manage and monitor the primary and secondary standby servers and replicate mission critical data across two or more database servers.

ZRS simplifies maintenance

Only one primary storage can work at a time. In case of primary storage failure, upgrade or maintenance issues secondary storage can be configured to be the primary one. Applications quickly reconnect to the new ZRS server. Secondary storage can be taken off-line for repairments, backups and system upgrades. After going online again secondary storage updates from the primary storage again. ZEO secondary storages can take care of all Zope traffic for the more static websites with small number of updates. Secondary storage makes routine maintenance more manageable as it can be shifted to the primary position for the time of maintenance work. Secondary servers can be added to the system at any time.

Interested in ZRS?

Contact Quintagroup to know more about ZODB replicated storage implementation for your website.

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