Consequences of not mirroring

If you do not mirror your dbspaces, the frequency with which you must restore from a storage-space backup after media failure increases.

When a mirror chunk suffers media failure, the database server reads exclusively from the chunk that is still online until you bring the down chunk back online. When the second chunk of a mirrored pair goes down, the database server cannot access the data stored on that chunk. If the chunk contains logical-log files, the physical log, or the root dbspace, the database server goes offline immediately. If the chunk does not contain logical-log files, the physical log, or the root dbspace, the database server can continue to operate, but threads cannot read from or write to the down chunk. If an unmirrored chunk goes down, you must restore it by recovering the dbspace from a backup.


Copyright© 2019 HCL Technologies Limited