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Adabas Recovery using “fast backup” software. by Rich Crumley Keane, Inc. SAG disclaimer.
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Adabas Recoveryusing “fast backup” software by Rich Crumley Keane, Inc
SAG disclaimer “Software AG does not recommend using such a database fastcopy as a substitute for a regular Software AG database (or delta) save. Not only does Software AG have no control over the datasets that are included in the database fastcopy, but it also cannot vouch for the success of the fastcopy. Moreover, delta saves cannot sensibly be run on a copy of the database, as the DSF status change effected by the delta save would occur on the database copy instead of the original.”
Agenda • Backup process • Recovery process • Some possibilities
The Backup Process • Suspend update transactions • Execute “fastcopy” • Resume update transactions
TRANSACTIONS SUSPEND Optional Parameter - TTSYN “Use this parameter to specify the maximum amount of time the nucleus is to wait for all ET users to reach ET status before it forcibly ends and backs out update transactions that are still running in order to quiesce the system. If this parameter is not specified, the default is the ADARUN TT value.”
TRANSACTIONS SUSPEND Optional Parameter - TRESUME “Use this parameter to specify the amount of time in seconds the system is to remain quiesced after being suspended before the nucleus automatically resumes normal update transaction processing. If this parameter is not specified, the default is 120 seconds and the maximum is 86400 seconds or about 24 hours. The count begins when the nucleus has been successfully quiesced. ”
TRANSACTIONS SUSPEND Behind the scenes: • New update transactions held in the user queue. • In-flight transactions are allowed to complete (within TTSYN) • Buffer flush • Write checkpoint SYNC-73 • ADADBS notified
TRANSACTIONS SUSPEND Issues: • Read processing continues • Utility conflicts (collisions) • TTSYN value • TRESUME value
TRANSACTIONS RESUME Behind the scenes: • Write checkpoint SYNS-74 • Suspended transactions released from the user queue • ADADBS notified
TRANSACTIONS RESUME Issues: • Database not in SUSPEND status
Agenda • Backup process • Recovery process • Some possibilities
The Recovery Process Database recovery: • Ensure database inactive • Execute “copyback” process • Start database in utility only mode • Regenerate transactions • Start database for normal processing
The Recovery Process File recovery: • Disable original file • Regenerate transactions on “snap” DB • Save file on “snap” database • Restore file to original database • Enable file for normal processing
Agenda • Backup process • Recovery process • Some possibilities
Some Possibilities How might the “snap” database be used? • Offline Save • Diagnostic utilities (ACK, ICK, VAL) • Static copy of Production database • Recovery purposes • ???