Setting Up Parallel Archive (ON-Archive) (SAP Library - SAP Database Guide: Informix (BC-DB-INF-DBA))

Setting Up Parallel Archive (ON-Archive)

Use

To create a parallel archive of your Informix database with ON-Archive , you must have more than one volume set and more than one tape device since the data must be written in multiple streams at the same time. Parallel archive is not possible with ontape .

You can create a parallel archive in either of the following ways:

With the DBA Planning Calendar of the Computing Center Management System (CCMS). For more information, see Archiving or Backing Up the Database in the DBA Planning Calendar (Informix).

Manually. To do this, you enter ON-Archive commands outside CCMS.

Procedure

Whichever method you choose to create parallel archives, you need to meet the following requirements:

Define multiple tape devices.

You associate a logical tape device with a physical tape device in the config.arc file. For more information, see the DEVICE parameter in Editing the config.arc File for ON-Archive. Define a set of entries similar to the following example (the logical device is on the left, the physical device on the right):

DEVICE DBTAP0_VOP = /dev/rmt/0m
DEVICE DBTAP3_VOP = /dev/rmt/3m
DEVICE DBTAP5_VOP = /dev/rmt/5m

You also need to have enough tape drives. Make sure that a tape drive is left for logical-log backup. Otherwise, you run the risk that logical-log backup cannot proceed, which might cause the database to stop.

Define multiple volume sets.

The logical devices that you defined in the first step must be assigned to a series of volume sets. Refer to Setting Up Volume Sets and Volumes for ON-Archive Without SAP Scripts. Define a series of volume sets, as in the following example:

$ onarchive ‘DEFINE/VSET=DBTAP0/DEVICE_TYPE=DBTAP0_VOP/
DRIVER=TAPE/ACCESSIBILITY=0/CLASS=SYSTEM'

$ onarchive 'DEFINE/VSET=DBTAP3/DEVICE_TYPE=DBTAP3_VOP/
DRIVER=TAPE/ACCESSIBILITY=0/CLASS=SYSTEM'

$ onarchive 'DEFINE/VSET=DBTAP5/DEVICE_TYPE=DBTAP5_VOP/
DRIVER=TAPE/ACCESSIBILITY=0/CLASS=SYSTEM'

Result

If you used the example here, you can now start a parallel archive using three separate streams to each of the following volume sets:

DBTAP0 on logical tape device DBTAP0_VOP using physical device /dev/rmt/0m

DBTAP3 on logical tape device DBTAP3_VOP using physical device /dev/rmt/3m

DBTAP5 on logical tape device DBTAP5_VOP using physical device /dev/rmt/5m

You can perform this with the DBA Planning Calendar in CCMS (recommended) or by entering ON-Archive commands manually (more errors possible).