When MVS™ detects a loss of connectivity, MVS determines the viability of rebuilding each structure affected by the connectivity loss.

If MVS determines that there is an active SFM policy in the sysplex:

1. MVS verifies that the SFM policy data is at the same level on all systems.
2. MVS checks the active CFRM policy to see if a rebuild percent value has been specified for affected structures, or takes the default rebuild percent value of 1.
3. MVS calculates the total system weight of (A) all systems containing at least one active connection to the structure in the coupling facility to which connectivity has been lost, and (B) all systems having at least one active connection to the structure. Note that if there are multiple users of a structure on one system, that system weight is counted only once.

   For example, if a structure has one connection per system and all systems are of equal weight 10, then in an eight-system sysplex if one system lost connectivity the value of A (total system weight of all systems containing an active connection that have lost connectivity) is 10 and the value of B (total system weight of all systems containing an active connection) is 80.

4. MVS determines what action is to be taken and informs the connected users through event exit processing.
   The determination is arrived at by dividing A by B, multiplying by 100, and then comparing the result with the rebuild percent for the structure in the CFRM policy.

   • If the result is greater than or equal to REBUILDPERCENT, then MVS initiates a user-managedrebuild.
   • If the result is less than REBUILDPERCENT, MVS does not initiate a rebuild.

   In this example, (10/80)*100 would be the value compared to the REBUILDPERCENT value. If the value of REBUILDPERCENT was 13 or higher, a rebuild would not be initiated.

If MVS determines that there is not an active SFM policy in the sysplex, MVS initiates user-managed rebuild for loss of connectivity to a structure, regardless of the REBUILDPERCENT specification.