Method to manage path failure threshold consensus

An apparatus to minimize performance degradation during communication path failure in a data processing system, the data processing system comprising a plurality of host computers, a storage controller and a plurality of physical paths in communication with the host computer and the storage controller, the apparatus comprising:

• means for establishing a threshold communication path error rate via a failure threshold command for each of the plurality of host computers;
• means for determining whether the plurality of host computers share a common resource corresponding to respective threshold communication path error rates;
• means for performing a consensus operation on the respective threshold communication path error rates to identify a preferred threshold communication path error rate, the consensus operation enabling avoidance of performance degradation due to conflicting threshold communication path error rates;
• means for determining an (i)th actual communication path error rate for an (i)th physical communication path, wherein said (i)th physical communication path is one of said plurality of physical communication paths in communication with said host computer and said storage controller;
• and,
• means for discontinuing use of said (i)th physical communication path if said (i)th actual communication path error rate is greater than said preferred threshold communication path error rate;
• and wherein
• each of the plurality of host computers comprises at least one channel path identifier (CHPid);
• the failure threshold command for a respective host computer enables provision of path failure threshold rules to determine when a CHPid has reached a failed state condition;
• the failure threshold command enables at last one of the plurality of host computers to have control over path failures detected by a storage controller;
• and,
• the failure threshold command enables at least one of the plurality of host computers to configure the path failure threshold rules for all CHPid, equally for all CHPid that comprise a path group, differently for each CHPid, or a combination based on a number of paths available at a time of a path failure detection.

A data processing system comprising

• a plurality of host computers,
• a storage controller;
• a plurality of physical paths in communication with the plurality of host computers and the storage controller;
• and,
• a system for minimizing performance degradation during communication path failure in a data processing system, the system comprising instructions for:
• establishing a threshold communication path error rate via a failure threshold command for each of the plurality of host computers;
• determining whether the plurality of host computers share a common resource corresponding to respective threshold communication path error rates;
• performing a consensus operation on the respective threshold communication path error rates to identify a preferred threshold communication path error rate, the consensus operation enabling avoidance of performance degradation due to conflicting threshold communication path error rates;
• determining an (i)th actual communication path error rate for an (i)th physical communication path, wherein said (i)th physical communication path is one of said plurality of physical communication paths in communication with said host computer and said storage controller;
• and,
• discontinuing use of said (i)th physical communication path if said (i)th actual communication path error rate is greater than said preferred threshold communication path error rate;
• and wherein
• each of the plurality of host computers comprises at least one channel path identifier (CHPid);
• the failure threshold command for a respective host computer enables provision of path failure threshold rules to determine when a CHPid has reached a failed state condition;
• the failure threshold command enables at last one of the plurality of host computers to have control over path failures detected by a storage controller;
• and,
• the failure threshold command enables at least one of the plurality of host computers to configure the path failure threshold rules for all CHPid, equally for all CHPid that comprise a path group, differently for each CHPid, or a combination based on a number of paths available at a time of a path failure detection.