Disaster Recovery (Backup Site) for Printers

There are two situations where a backup site for printing is essential.

In data centers with only one or a few AFP printers (main printer). For example, situations when the printer is out of order in the middle of the night during end-of-month processing can and do occur.
Data centers that have peak periods but normally print lower amounts of output may prefer to do some of their peak day printing at another site. This method avoids the need to purchase more printers that are used only on peak days.

Without AFP, in order to print at a backup site, a copy of the SYS1.IMAGELIB dataset had to exist at the backup site. However, only one SYS1.IMAGELIB dataset is allowed per CPU and each CPU must have a SYS1.IMAGELIB dataset. The backup site also has a SYS1.IMAGELIB of its own. If even one definition (for example, font shape) is not identical for both sites, then the backup site cannot be used for printing. What generally occurred to avoid this restriction was that the resident SYS1.IMAGELIB dataset was temporarily replaced, which was inconvenient and less than productive.

AFP, however, does not require the use of SYS1.IMAGELIB. AFP printing characteristics can be defined in any number of libraries on a single system. In addition, different libraries can be defined to different printers, using the same PSF procedure. A copy of the AFP libraries is all that is required at the backup site.

Using the JES OFFLOAD facility, Control-D bundles can be downloaded to tape or cartridge retaining all printing characteristics and the correct sequence of the bundle. Reports can be printed on a backup site printer, regardless of whether or not Control-D is installed at the backup site.

Preparing for Backup Site Printing

There are two locations at which preparations for backup site printing must be made:

The data center.
The backup site data center.

Preparations in the Data Center

A special document of instructions must be prepared for the operators who perform the backup site printing. The document must include all of the steps that they must perform.
A number of OFFLOADers can be defined to JES. It is most convenient to have one of the OFFLOADers already defined with all the required parameters. For a detailed description of the required OFFLOAD parameters, refer to the JES Operator’s Guide.

Special consideration for the OFFLOAD selection criteria parameters must be taken depending on the chunking method used. This is to ensure that only Control-D bundles are transmitted to the OFFLOAD facility.
- If not using the chunking mechanism, that is, if CHUNKSIZE is set to 0, the Control-D Printing monitor name (that is, CTDPRINT) must be specified as the job name that OFFLOAD must select from spool. The following command demonstrates how this may be specified to the OFFLOADer:
  Copy
```
$TOFFx,JOB=CTDPRINT,WS=(JOB)
```
  Note that the WS (Work Selection Criteria) parameter must also be updated. The x must be replaced with the OFFLOADer identification number.
- If using the chunking mechanism, that is, if the value of CHUNKSIZE is greater than one, the logical printer destination (for example, U1001, as specified in CTDPARM) must be used as the destination selection criteria. The following command demonstrates how this may be specified to the OFFLOADer:
  Copy
```
$TOFFx,R=U1001,WS=(R)
```
  Note that the WS (Work Selection Criteria) parameter must also be updated. The x must be replaced with the OFFLOADer identification number.

The AFP external printing characteristics must be available at the printing backup site data center. This can be made available in one of a number of ways:
- Adding an additional step to the printing backup site procedure and copying the AFP external printing characteristics libraries onto tape or cartridge while transmitting the bundles to the OFFLOAD facility. Using a simple IEBCOPY utility (or equivalent) is sufficient.
- Having a copy of the AFP external printing characteristics at the printing backup site data center at all times (that is, prepared in advance). This way, there is no need to copy the external printing characteristics libraries to the printing backup site data center while in the transmitting process.

No special preparations need to be performed in Control-D.

Preparations in the Backup Site Data Center

As with the OFFLOAD preparations at your data center, there must be an OFFLOADer prepared at the printing backup site, ready to be used with all relevant OFFLOAD parameters.
The printer at the printing backup site usually needs to be dedicated to the bundles. To achieve this, the same guidelines used to transmit only Control-D bundles to the OFFLOAD facility at your site can be used in order to print only your particular bundles at the backup site printer.
- If not using the chunking mechanism, that is, if CHUNKSIZE is set to 0, the Control-D Printing monitor name (that is, CTDPRINT) must be specified as the job name the printer selects from spool. The following command demonstrates how this may be specified to the printer:
  Copy
```
$TPRTx,JOB=CTDPRINT,WS=(JOB)
```
- If using the chunking mechanism (that is, CHUNKSIZE greater than one), the logical printer destination (for example, U1001, as specified in CTDPARM) must be used as the destination selection criteria. The following command demonstrates how this may be specified to the printer:
  Copy
```
$TPRTx,R=U1001,WS=(R)
```
Prepare a PSF procedure that has your AFP external resource libraries concatenated.
Note that the printing backup site does not have to have Control-D installed. At the printing backup site, the printing process is totally independent of Control-D and uses JES facilities only.

Disaster Recovery Flow

Once the above preparations for the backup site printing have been made, you are ready for printing at the backup site. Hopefully a disaster will not occur, but if it does, the following procedure must be performed:

In Your Data Center

Start the OFFLOAD facility using the appropriate JES DEVICE operator command.
Trigger the Control-D printing mission.
If the AFP external printing characteristics resources are not prepared in advance at the printing backup site, copy the resources to tape or cartridge.

Wait for the printing mission to finish and wait for all chunks on spool to be transmitted to the OFFLOAD facility. Then close the OFFLOAD facility using the appropriate JES operator command.

At the Printing Backup Site Data Center

If the AFP external printing characteristics resources were not prepared in advance at the printing backup site, copy the resources to DASD at the printing backup site.
Start the printer using the special PSF procedure that has your AFP external printing characteristics resource libraries concatenated.
Start the OFFLOAD in order to receive your bundles to the printing backup site’s spool.
Issue the relevant JES commands to the printer (as described above in preparations at the printing backup site).
When all printing is finished, close the printer. The OFFLOAD facility automatically closes itself once all bundles are received on the printing backup site’s spool.

Printing Backup Site Summary

As described above, a number of tasks must be performed in advance in order to implement the disaster recovery (backup site) for printers, but it is well worth the effort. Large savings may very well be realized for those sites that implement this option.