SQL/MX 3.2.1 Management Manual (H06.26+, J06.15+)

10 Performing Recovery Operations
The success of recovery operations depends on the effectiveness and consistency of the plan you
develop for handling recovery situations. (See “Planning Database Recovery” (page 45)) Before
beginning a recovery operation, you should thoroughly evaluate the tools available (RDF, TMF
online dumps, backup tapes, and so forth) and appropriate for the type of failure.
This section addresses these topics:
• “Recovering Databases After Disk or Node Failures” (page 235)
• “Recovering Disk Volumes” (page 235)
• “Recovering Files” (page 236)
• “Recovering Metadata” (page 239)
• “Recovering Database Objects” (page 239)
• “Restoring Objects With BRCOM RESTORE” (page 251)
• “Repairing Damaged SQL/MX Metadata and Objects” (page 253)
• “Using GOAWAY to Delete Damaged Objects” (page 263)
• “Recovering From SCF Commands” (page 263)
This section generally contains information specific to recovering SQL/MX database objects. For
more information about recovering SQL/MP objects, see the SQL/MP Installation and Management
Guide and the Backup and Restore 2 Manual.
Recovering Databases After Disk or Node Failures
When a disk or node (system) fails, SQL/MX tables and database files on the disk or node are
often left in a crash-open state. To recover the database, both the catalogs and the files must be
recovered to a consistent state.
Normally, TMF volume recovery automatically recovers the database after a disk or node failure.
See “Recovering Disk Volumes” (page 235). However, if one or more disks have media failures
and cannot be recovered by volume recovery, use TMF file recovery. See “Recovering Files”
(page 236). You have these options:
• Use the file recovery method to recover the database, starting with online dumps, which include
files containing copies of consistent catalogs and objects saved by the TMF DUMP FILES
command. The file recovery function starts with saved files and updates transactions to the
last consistent point in the audit trails.
• Use the file recovery method with a specified TIME option to recover a database to a given
consistent time, as described in “Recovering Files With the TIME Option” (page 236).
Recovering Disk Volumes
TMF volume recovery is invoked automatically by the START TMF command and is invoked as
needed thereafter when a volume becomes accessible. Volume recovery uses the audit trails to roll
back incomplete transactions and return the database to the last consistent state.
Volume recovery might fail to recover a volume or a file. Possible recoverable cases are:
• A volume becomes unavailable during the volume recovery operation. When you bring up
the volume, TMF automatically restarts volume recovery.
• A file is corrupted or inconsistent in such a way that volume recovery cannot apply the audit
trail information. If volume recovery fails to recover a file, FILEINFO displays REDONEEDED
Recovering Databases After Disk or Node Failures 235