Interaction Between AP and DR

7

Dynamic Reconfiguration (DR) and Alternate Pathing (AP) are designed to work closely together. DR allows you to attach and detach system boards without bringing down your Sun server, as described in the Dynamic Reconfiguration User's Guide. AP allows you to switch usage away from an adapter on a board that is being detached or possibly to an adapter on a board that has been attached. You must perform the switch manually via apconfig(1M) with its -P option, as shown in the previous two chapters.

DR notifies the AP Daemon of the current status of a DR operation. (The AP Daemon is described in Chapter 10, "AP Components".) The AP Daemon uses this information to restrict certain operations. If an adapter is on a board that is being drained, AP marks it with a DR flag; if it is on a board that is detached, AP marks it with a DE flag. AP does not let you switch any adapters that have DR or DE flags. When a board is in the Attached state, AP does allow you to switch to any alternates on that board.

The following AP command shows that the pln0 controller is detached and, thus, unavailable. AP would disallow any attempt to switch to pln0 while the board it is on is in this detached state.


  # ./apconfig -S  
  
  c1      pln0  P A  
  c2      pln1  DE  
          metadiskname(s):  
                  mc1t5d0  
                  mc1t4d0  
                  mc1t3d0  
                  mc1t2d0  
                  mc1t1d0

When you plan to detach a board, you can switch away from adapters on that board at any time prior to a detach operation, or even during the Init Detach and drain states of a detach operation. However, you must perform any necessary switching before you enter the Complete Detach state, or the detach operation will fail. In this case, you can perform the switch and retry the detach operation. For more information about DR, see the Dynamic Reconfiguration User's Guide.

Notes

If you attach a board that has an SSA path you must execute apconfig -F to clear the DR Detach flag for that board.

If you DR Detach a board that has a network device, and that network device has not been used since the previous boot, you must run apconfig -F to notify the system that the network device is no longer available.

Output of the apconfig -N command may incorrectly show a network as DR Detached or Present if its controlling AP meta-driver has not been loaded. Run apconfig -F to ensure correct information.