ECS quiesces activity by turning off the autoadd function and removing all ECS-active catalogs from the ECS structure. All catalogs then revert to VVDS sharing mode. ECS activity is quiesced in a sysplex when one of the following events occur:

• An ECS-active system normally disconnects from the ECS structure. A normal disconnect means that the system issuing the disconnect continues to function and make catalog requests. In this situation, ECS activity is quiesced to ensure that catalog requests on the disconnected system are not rejected because catalogs are ECS-active on other systems. Both CAS restarts and IPLs are considered abnormal disconnects and do not result in quiescing ECS activity. A normal disconnect is initiated by the MODIFY CATALOG,ECSHR(DISCONNECT) command.
• A rebuild of the ECS structure is initiated. This can be done by an operator, another component, or by ECS when it is informed of an ECS structure failure or loss of CF connection. ECS activity is quiesced for the life of the rebuild. Once the rebuild has completed without error, ECS restores the ECS state at the time the rebuild was initiated; that is, if autoadd was on when the rebuild was initiated, autoadd is reactivated and all eligible catalogs are re-enabled automatically by ECS. If autoadd was not on when the rebuild was initiated, autoadd will not be activated at the completion of the rebuild. If a CF error occurs during an ECS rebuild, the customer must manually reactivate ECS after the CF has stabilized.