Transcript Adabas Recovery Using “fast backup” Software

Adabas Recovery
using “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
ADABAS 7.4 Release Notes
SUSPEND 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
Execute “fastcopy”
RESUME UPDATE TRANSACTIONS
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
• ???