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Online redundancy migration for ASM diskgroups

RobertOrtel
RobertOrtel Member Posts: 66 Blue Ribbon
edited Jan 11, 2016 6:18PM in Database Ideas - Ideas

Redundancy upgrade for ASM diskgroups can only be done through downtimes. Best tip seems to be to restore the database on a higher redundancy diskgroup. But as disk loss and disk resync does already work with normal or high redundancy diskgroups during the repair of disk failures, it does not seem to be that hard to just add a new failure group to a diskgroup, run the rebalance and so upgrade the redundancy in an online fashion.

The same applies for dropping failure groups to downgrade redundancy.

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Comments

  • Franck Pachot
    Franck Pachot Member Posts: 912 Bronze Trophy

    In 12c EE that can be done without downtime as datafiles can be moved online.

  • RobertOrtel
    RobertOrtel Member Posts: 66 Blue Ribbon

    In 12c EE that can be done without downtime as datafiles can be moved online.

    Good to know. Wasn't in touch with this 12c feature yet.

    Yet another drawback of the backup/restore method next to the downtime are the space requirements: imagine you want to migrate from normal to high redundancy, so you are required to have 5 times the disk space available of the data you want to store. With huge DBs this might become and issue.