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 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.
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.
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.
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.
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.