TurboIMAGE/XL Database Management System Reference Manual MPE/iX V6.5 (30391-90011)

Chapter 7 331
Logging and Recovery
Logging Preparation
NOTE If you plan to restore the TurboIMAGE/XL database on an MPE V system,
use the TRANSPORT option of the DBSTORE or STORE command. Chapter 8
contains detailed information about the DBSTORE command. Refer to the
MPE/iX Commands Reference Manual for more information about STORE
options.
TurboSTORE/iX 7x24 True-Online Backup
This section describes the use of TurboSTORE/iX 7x24 True-Online Backup with the
ONLINE=START or ONLINE=END option.
When multiple databases and related files are involved, you may use the MPE/iX STORE
command (with or without the ONLINE=START or ONLINE=END option) to collectively
copy them to tape or other storage media and, if necessary, collectively restore them by
using the MPE/iX RESTORE command. You need to have either SM or OP capability to do
this and should have an understanding of the standard rules and features associated with
STORE and RESTORE. Note that when using the STORE command without the
ONLINE=START or ONLINE=END option, neither the DBSTORE flag nor the time stamp
(signifying the date and time the backup copy was made) is set in the database root file.
When you use MPE/iX STORE command (with the option ONLINE=START or
ONLINE=END), you are using TurboSTORE/iX 7x24 True-Online Backup which does the
following:
1. Backs up multiple databases along with their related files including the TC file,
third-party index files, jumbo data set files, and B-Tree index files.
2. Sets DBSTORE flag in the root file(s)
3. Sets the time stamp designating the date and time of the backup operation before
storing the database.
4. Quiesces the database if it is open for write access. The database is quiesced at a point
when no active transaction is in progress.
5. Posts log records if enabled for logging, designating the beginning and end of quiesce.
DBRECOV uses these records to determine the starting point of the roll-forward recovery.
The most significant advantage is that your database can even be open for access when you
start the backup process and can continue to remain open for access. The backup becomes
a True-Online Backup.
When performing a True-Online backup, there is a point in time when the backup
occurred, especially when the database is open for modification. This is helpful when
performing a roll-forward recovery to ensure that all files are in a logically consistent state
at the same time for backup and later a subsequent restore for recovery. This point is
called the
sync point , where all data set files are synchronized. Also, it means this is the
point when the TurboIMAGE/XL database is quiesced for a short duration, that is, it is in
a logically consistent state and there is no active transaction in progress. All ongoing
transactions, if any, are allowed to be completed before the
sync point .
The ONLINE=START option allows the
sync point at the beginning of a True-Online