Even though database files generally constitute the largest part of any
backup, TurboSTORE/iX 7x24 True-Online Backup also backs up system and
non-database files. Since TurboSTORE allows changes to files during
a backup, it establishes a close tie to the file system to ensure physical
and logical consistency.
Physical Consistency |
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Physical consistency is ensured by providing a snapshot of the fileset
at a specific point in time, specifically, at the sync point. This is
adequate for files that are not "related" to other files, and have no
dependencies on changes to other files. This includes system files,
some flat files and any other files not associated with a database.
For KSAM XL files and files enabled for transaction management,
TurboSTORE guarantees that no partial transactions are included
in the copy of the file stored on the tape. This ensures that a consistent
copy of the file is stored.
If Native Mode Message files are open during the sync point,
TurboSTORE follows the necessary steps to successfully imitate
closing the file to ensure data integrity, physical consistency, and
recoverability.
User-mapped files are managed the same way they were with as TurboSTORE/iX
II with Online Backup. Whenever changes are made to a user-mapped
file being stored by a 7x24 true-online backup, the entire file is copied to
TurboSTORE's log files. However, if a user-mapped file is left open
for write access across the sync point, then TurboSTORE captures
the last known state of the file, which would either be at the last
FOPEN, FCLOSE, or FCONTROL 6. If TurboSTORE does not
capture any of these events, the file is stored in whatever
state it was in when TurboSTORE opened the file, which may be inconsistent.
A warning message is printed for all user-mapped files open across the sync
point.
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 | NOTE:
Compatibility mode (CM) files, namely Circular (CIR) files, and Relative
I/O (RIO) files have internal buffer structures that cannot be logged
by TurboSTORE. If these files are open for write access during the sync
point, TurboSTORE captures their last known state, which is either
since the last FCLOSE or the last FCONTROL 6. A warning is
issued for all CM files that were open across the sync point. |
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Logical Consistency |
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In addition to physical consistency, TurboSTORE/iX 7x24 True-Online
Backup also guarantees logical consistency for databases. This is done
by setting the sync point to occur when all open transactions against
the databases have completed. No new transactions can start until the
open transactions are complete, which is called quiescing the database.
Although any type of database can be stored by TurboSTORE, only
TurboIMAGE and ALLBASE/SQL databases are automatically quiesced using
special database intrinsics.
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 | NOTE:
Quiescing an ALLBASE/SQL database and storing the ALLBASE/SQL database
by TurboSTORE/iX 7x24 True-Online Backup when the DBEnvironment is in
normal use, has the same effect as using the STOREONLINE command of
SQLUtil. For a 7x24 true-online backup of ALLBASE/SQL to be of use for
rollforward recovery, use the same procedures you would use when doing
the STOREONLINE commands. |
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If you need to synchronize any other file types (e.g., CM file types
such as CIR files and RIO files) and/or any third-party databases that
are not automatically synchronized, you can manually quiesce these
before beginning the backup, or during the backup by specifying the
ASK parameter with the ONLINE option. ASK makes TurboSTORE
wait at the sync point while you finish these operations. Refer to
"Prompting During Backup (ASK)" later in this chapter for a description
of the ASK parameter.
Once all files and databases are quiesced, TurboSTORE establishes the
logically consistent synchronization point. It then unquiesces all
TurboIMAGE and ALLBASE/SQL databases.
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 | NOTE:
Only open databases being stored by a TurboSTORE/iX 7x24 True-Online Backup
are quiesced. If a database is being stored, but is not opened for
write access, it is not quiesced. |
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