Exadata - Two Seldom used attributes

Exadata is a one of the most powerful product from Oracle, probably the most powerful engineered system available for consumer business on the planet.

Today I talk about few features which I have seen Administrators missing or not using them a lot.

Appliance mode 

appliance.mode is a disk group attribute which improves the disk rebalancing times so redundancy is restored much faster after a disk drop operation or post failure

DMA who have upgraded the release 11.2.3.3.0 (yes it is available from this release) can use this attribute. This needs to be set at the ASM level and can be set using below SQL statement

ALTER DISKGROUP <disk_group> SET ATTRIBUTE 'appliance.mode' = ['TRUE'|'FALSE'];

As with all the Oracle Features there are restrictions when setting this 2 key ones are – compatible.asm is set to 11.2.0.4 or higher on the disk group and cell.smart_scan_capable is set to True.

Content Type

Oracle introduced with 11.2.0.3 a new parameter content.type for ASM which takes 3 different values data, recovery and system. Each type of setting modified the adjacency measure used by secondary extent placement algorithm.

Using these settings, the likelihood of double failure  (in Normal redundancy DG) causing Data loss reduced.

Having this attribute in effect would require rebalancing, so it would be good to rebalance in a quite time.

Alter diskgroup data set attribute 'content.type'='data';

Alter diskgroup data rebalance power <power>;