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Trove/volume-data-snapshot-design

< Trove
Revision as of 19:16, 9 April 2014 by Denis M. (talk | contribs) (Configuration)

Data volume snapshot

Description

Volumes Snapshots

This introduction provides a high level overview of the two basic resources offered by the OpenStack Block Storage service. The first is Volumes and the second is Snapshots which are derived from Volumes.

Volumes

Volumes are allocated block storage resources that can be attached to instances as secondary storage or they can be used as the root store to boot instances. Volumes are persistent R/W Block Storage devices most commonly attached to the Compute node via iSCSI.

Snapshots

A Snapshot in OpenStack Block Storage is a read-only point in time copy of a Volume. The Snapshot can be created from a Volume that is currently in use (via the use of '--force True') or in an available state. The Snapshot can then be used to create a new volume via create from snapshot.

Workflow

  1. flush database to disk and place in read only mode (specific per datastore)
  2. run cinder snapshot (backup)
  3. turn database writes back on

Justification/Benefits

Justification

Data could be backued in two ways:
  1. Standart backup strategies (innobackupex, nodetoolsnapshot) + Swift container (already implemented).
  2. Snapshot of the attached block storage (not implemented).
Basically, its the another way of backupin' data through standard OpenStack capabilities.

Benefits

Generic way to backup the data. This feature is not the datastore-type/version specific.

Impacts

Changes the behavior to the backups made by Trove, it impacts at already implemented backuping process through native database tools (mysqldump, nodetool, etc.) and the Swift as storage container service. Changes are backward compatible.


Configuration

Configuration parameters are guest specific.
Name Type Default Available variants
backup_agent String trove.guestagent.backup.backupagent.SwiftAgent trove.guestagent.backup.backupagent.CinderAgent
storage_strategy String Swift Cinder

Database

No changes


Public API

No changes

Internal API


From trove-api to trove-taskamanger

No changes


From trove-taskamanger to trove-guestagent

No changes

Guest Agent


Changes are backward compatible. Changes will be available for all datastores. This method of the backuping is generic for the all datastores types/versions.