STORE and TurboSTORE/iX Products Manual (B5151-90003)

116 Chapter6
STORE and TurboSTORE/iX Command Options
TurboSTORE/iX 7x24 True-Online Backup Options
When online backup begins, the shadow subsystem assigns each file in the store fileset to a
log file created on the same volume where the file resides. Actual logging activity does not
take place unless the file is modified after the attach phase.
TurboSTORE saves the changes made to databases and files being stored in special log
files. These files can become quite large when there is a lot of activity on the system. The
LOGVOLSET option allows you to specify which volume set to use for the log files. You can
use this feature with the log file size summary statistics from previous backups to ensure
that there is enough disk space for the online backup log files. The log volume set is
specified as follows:
:STORE /;*tape;ONLINE;LOGVOLSET=volumeset
The amount of log space required is directly proportional to the amount of modifications
performed against the attached file. Therefore, the more modifications made to an
attached file, the more log space required. In the worst case, the maximum amount of log
space required equals the sum of the space required for all of the files being stored. By
storing the heavily modified files first, you reduce the amount of logging space required.
Reducing the amount of logging data written to the backup media will also reduce the time
required to restore the files.
As each piece of backup media is filled, logging is disabled for the files that were stored on
that media.
Use the ONLINE parameter of STORE to perform an online backup. Before the STORE process
is initiated, you must warn the users to close all files to ensure that the files are both
physically and logically consistent. For example, the following message can be sent:
WARN @S;ONLINE BACKUP WILL BEGIN IN TEN MINUTES.
WARN @S;PLEASE CLOSE YOUR FILES.
Begin the online backup by specifying the ONLINE parameter with the STORE command.
For example, the following illustrates the STORE command for an online backup.
:STORE @.@.@;*T;DIRECTORY;ONVS=MPEXL_SYSTEM_VOLUME_SET,NV1;ONLINE
When online backup begins, all files not currently open for write are attached to a log
handler known as the shadow subsystem. Once the attach phase is complete, STORE issues
the following message to the console.
FILES LOCKED BY ONLINE STORE ARE NOW FREE FOR READ/WRITE/PURGE
This message is also written to $STDLIST if STORE is being run from a session. After you
receive the above message, the users are allowed read, write and purge access to the
attached files. Send your users a message telling them they may resume their applications.
For example:
WARN @S;ONLINE BACKUP HAS BEGUN.
YOU MAY NOW RESUME YOUR APPLICATIONS.
The NOTIFY option (described earlier in this chapter) can be used to automate this task.
If any files were still open at the time you started online backup, you will receive the
following message:
! NOT STORED: FILE OPEN FOR WRITE AT ATTACH