Benefits of geographic mirroring

 

This topic describes benefits of geographic mirroring.

Geographic mirroring provides these benefits:

• Geographic mirroring provides site disaster protection by keeping a copy of the independent disk pool at another site which can be geographically distant. Having an additional copy at another geographic dispersed site improves availability.

• Geographic mirroring provides high availability with more backup nodes than switchable independent disk pools. In addition to having a production copy and mirrored copy, backup node possibilities are expanded when the independent disk pool is configured as switchable in an expansion unit (frame/unit), on an IOP on a shared bus, or on an IOP that is assigned to an I/O pool.

The geographically mirrored independent disk pool maintains all of the benefits of an independent disk pool, with its ability to be made available or unavailable as well as allow flexibility for the following actions:

• You can protect the production copy and mirror copy with your choice of protection, either disk unit mirroring or device parity protection. The production copy and mirror copy are not required to have the same type of protection.

• You can set the threshold of the disk pool to warn you when storage space is running low. The system sends a message, allowing you the time to add more storage space or to delete unnecessary objects. If the user ignores the warning and the mirror copy disk pool becomes full, geographic mirroring is suspended. If the user ignores the warning and the production disk pool becomes full, the application stops and objects cannot be created.

• The mirror copy can be detached and then separately made available to perform save operations, to create reports, or to perform data mining. When the mirror copy is reattached, it is synchronized with the production copy, and all modifications made to the detached copy are lost. Synchronization can be a lengthy process.

• If you configure the independent disk pools to be switchable, you increase your options to have more backup nodes that allow for failover and switchover methods.

 

Parent topic:

Geographic mirroring concepts

Related concepts
Mirrored protection concepts RAID 5 concepts

Related tasks
Setting the threshold of a disk pool

Related reference
Example: Independent disk pools with geographic mirroring