Tape Devices for Logical-Log Backup (ontape) 

Consider the following when planning the tape devices (that is, drives) for logical-log backup of your Informix database with ontape :

You need to define at least the device LTAPEDEV with a suitable physical device. Refer to Configuring Ontape.

Do not use /dev/null (UNIX) or nul (NT) for LTAPEDEV if you want to perform a restore of your system up to the time of failure.

If you specify a null value for LTAPEDEV , the logical-log files are marked as backed up as soon as they are full. Therefore, they cannot be backed up and the transactions recorded in these logs cannot be used for a logical restore.

SAP recommends that you have at least two tape devices, one for archives and one for logical-log backups. Otherwise, if your logical logs fill up when you are performing an archive, the database might stop processing. At the minimum, you must have one tape device (that is, drive) for logical-log backup.

Your devices must be fast enough to cope with the maximum rate at which the logical-log files fill. Local devices are more likely to cope than remote devices.

For continuous logical-log backup, you need to dedicate a terminal and a tape device to the logical-log backup. You should not use a remote device for logical-log backup because it is less secure than a local one.

 

See also:

Informix documentation