Starting mirrored protection

Use this procedure to start mirrored protection for a specific auxiliary storage pool (ASP) on your system.

Before you attempt to start mirrored protection, you should ensure that the ASP meets the requirements that are described in the Mirrored protection: Configuration rules topic. If you are performing several disk configuration and disk protection tasks, see the Configuring disks and disk protection topic to determine the correct sequence of steps for your situation.

To start mirrored protection, follow these steps:

If you are not already using dedicated service tools (DST), perform a manual IPL to start DST.
From the Use Dedicated Service Tools (DST) menu, follow these steps:
1. Select option 4 (Work with disk units).
2. Select option 1 (Work with disk configuration) on the Work with Disk Units display.
3. Select option 4 (Work with mirrored protection) on the Work with Disk Configuration display.

Select option 2 (Start mirrored protection) on the Work with Mirror Protection display.

                   Select ASP to Start Mirrored Protection
 
Select the ASPs to start mirrored protection on.
 
Type options, press Enter
  1=Select
Option   ASP   Protection
  _       1    Unprotected
  1       2    Unprotected

Select the ASP or ASPs to be mirrored on the Select ASP to Start Mirrored Protection display and press the Enter key.

You might see the following display:

                           Confirm Continuation
   To proceed, the system must perform directory recovery, which might take a 
significant amount of time.  The system might appear inactive during this time.
     
Press Enter to continue. Press F12=Cancel to return and change your choices.

Press the Enter key to continue.

The system shows a confirmation display of the new mirrored protection configuration, including the levels of protection.

Notice that half of the previous unit numbers for units being mirrored in the ASP no longer exist. The storage units for those unit numbers have been paired with the storage units for the remaining unit numbers to make mirrored pairs. Also notice that device parity units in the ASP have not been affected.

                      Confirm Start Mirrored Protection
 
Press Enter to confirm your choice to start mirrored
protection.  During this process the system will be IPLed.
You will return to the DST main menu after the IPL is
complete.  The system will have the displayed protection.
 
Press F12 to return to change your choice.
 
            Serial                  Resource
ASP  Unit   Number      Type Model  Name        Protection
  1                                             Unprotected
        1   00-48519    6606  030   DD010       Unprotected
  2                                             Mirrored
        2   00-1000341  9337  211   DD012       Disk Unit
        2   00-5000341  9337  211   DD015       Disk Unit
        3   00-0186325  6602  074   DD019       Device Parity
        4   00-0162516  6602  074   DD025       Device Parity
        5   00-0238703  6602  074   DD052       Device Parity

If the configuration is what you had planned and you do not have other configuration changes to make, skip to step 7.
If the configuration is not what you had planned, for example, the level of protection is less, you have the following options:
- Verify that the correct ASP was selected. Verify that any new storage units have been added to the correct ASP.
- Determine if additional hardware is required to achieve the planned level of protection.
- Determine if the existing hardware needs to be connected differently to achieve the planned level of protection. Contact your technical support organization for assistance.
- Consider continuing the start mirrored protection process which will provide better availability than non-mirrored protection, rather than waiting until additional hardware arrives so that you can achieve your planned level of protection. After you receive and install the additional hardware, use the Table 1 topic to determine the procedure for configuring your disk storage correctly. Even on very large systems, the tasks to stop mirroring, add units, and start mirrored protection can be done in several hours.
Place the system in Normal mode and press the Enter key to accept the configuration.
The system performs the first part of the process for starting mirrored protection. During that time, you are shown the Function Status display:
```
                              Function Status
   You selected to start mirrored protection.                 5 % Complete   
```
The system updates the display periodically.
Note: You can press F16 to return to the Use Dedicated Service Tools (DST) menu if you have other tasks to perform. However, you cannot perform any disk configuration tasks or end DST until the system has finished starting mirrored protection.

The system continues the start mirrored protection process in the What the system does when you start mirrored protection topic without further operator intervention.
After the system reaches the Command Entry display, you might want to create the QSYSMSG message queue to receive messages.
If you have this message queue, the system sends certain critical messages to it. You can monitor the message queue with a program to make sure the messages are not missed.