You must back up logical logs even when you use nonlogging tables because you must restore both storage spaces and logical logs.
Use onstat -g bus or onstat -g bus_sm to monitor logical logs and onbar-worker processes on each coserver in the current backup session. For more information, see Monitoring the Backup Scheduler Status.
Backing Up Logical Logs: |-- -b-- -l--+--------------+--+-----+--+-----------------+-----| '- -q--session-' '- -s-' +- -f--filename---+ | .-------------. | | V | | '---logstreamid-+-'
| Command | Purpose | Key Considerations |
|---|---|---|
| -b -l | Performs a backup of full logical-log files | The current logical-log file is not backed up. If you are using ISM, it also backs up the ISM catalog. |
| -b -l -f filename | Backs up the logstream IDs that are listed in
the text file whose pathname filename provides
Use this option to avoid entering a long list of logstreamids every time that you use this option. |
The filename can be any valid UNIX or Windows filename, including simple (listfile_1), relative (../backup_lists/listfile_2 or ..\backup_lists\listfile), and absolute (/usr/informix/backup_lists/listfile3 or c:\informix\backup_lists\listfile3) filenames. The file can list multiple logstreamids per line. |
| -b -l logstreamid | Uniquely identifies a logical-log stream that a given XPS coserver generates | If you supply more than one logstreamid, separate each item in the list with a space. A logstreamid is the same as a coserver ID. |
| -b -l -q session | Allows you to assign a name to the log backup
session
This name appears in the onstat utility so that you can follow the progress of the log backup. |
DBSERVERNAMErandom_number is the default session name. The session name must be unique and can be up to 128 characters. |
| -b -l -s | Salvages any logical logs that are still on disk after a database server failure | If possible, use this option before you replace a damaged disk. If you use onbar -r to perform a cold restore on an undamaged disk, ON–Bar automatically salvages the logical logs. For more information, see Salvaging Logical Logs. |
Use the LOG_BACKUP_MODE configuration parameter to specify whether to back up full logical-log files automatically or manually. If you change the value of LOG_BACKUP_MODE, you must restart the database server before the change takes effect.
If you set LOG_BACKUP_MODE to MANUAL, you must initiate a logical-log backup manually. To back up filled logical-log files manually, use the following command:
onbar -b -l
If you want to assign a session name to the log backup, use the -q option, as follows:
onbar -b -l -q "my_logbackup"
To back up the current log, use the following commands:
xctl onmode -l onbar -b -l
On Extended Parallel Server, you can start a continuous logical-log backup by setting the LOG_BACKUP_MODE configuration parameter to CONT. Whenever a logical-log file fills, the Backup Scheduler automatically starts an onbar-worker process, if one is not already active, and assigns the log backup to it.
To stop a continuous logical-log backup, you must suspend the backup session. For example, the following command turns off continuous logical-log backup for the session "log backup 1" on coserver 1. In a multicoserver environment, you might need to turn off logical-log backup on each coserver.
onbar off -q "log backup 1"
To find the logical-log backup session, use the onstat -g bus command. For more information, see Starting and Stopping ON-Bar Sessions (XPS).
If you set LOG_BACKUP_MODE to NONE, you cannot back up or restore logical logs, and log salvage does not work. Although you can continue to back up storage spaces, you cannot restore them. The only reason to set LOG_BACKUP_MODE to NONE is to test your system. Do not use LOG_BACKUP_MODE = NONE in a production system.
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