Data integrity monitoring among sysplexes with a shared direct access storage device (DASD)

摘要

System and method embodiments for monitoring data integrity among multiple sysplexes that share data sets on a DASD are provided. The virtual volume record (VVR) for each data set on DASD is configured with additional access fields that provide such information as the access mode (serial or multi-access), whether multiple systems have opened the data set, the names of an original sysplex and any additional sysplexes to open the data set, the names of the opening systems in each sysplex, job name and time stamp and a usage counter for each sysplex. Additional access logic in the OS on each system defines specific actions to be taken by the system OS when executing an “open” or “close” including reading and updating information in the additional access fields and generating error, warning or information messages to diagnostic logs. This allows serialization to be enforced among the sysplexes and for error messages to be issued for any system outside the original sysplex that tries to open the data set. This also enables allowing multiple sysplexes to have a data set open at the same time and to issue messages to that effect.

主权项

1. A system for monitoring data integrity, comprising:
a direct access storage device (DASD); a plurality of logical volumes defined on said DASD, each logical volume comprising a virtual storage access method (VSAM) volume data structure (VVDS) that includes a VSAM volume control record (VVCR), a VVDS self-describing volume record and a plurality of virtual volume records (VVRs), each VVR having fields that contain information related to a particular data set on the logical volume; and a plurality of computer sysplexes that share data sets on said DASD without means to communicate between the sysplexes to serialize access to the shared data sets, each said sysplex comprising one or more computer systems each configured to run an operating system (OS) that includes access logic to open and close data sets on said DASD; wherein said VVRs are configured to include additional fields for a sysplex name, a system name and a sysplex usage counter in a stack, wherein a sysplex to first open a first data set is designated as an original sysplex at the top of the stack until closed, said usage counter indicating the number of systems in the sysplex for which the first data set is open; wherein the OS access logic of a requesting system within the original sysplex is configured to grant an additional open request to the first data set, increment the usage counter and add information for the requesting system to the stack, to grant a close request to decrement the usage counter and remove the information for the requesting system in the original sysplex, and to remove the original sysplex from the stack when the usage counter reaches zero thereby allowing open requests from other sysplexes to open the first data set; and wherein the OS access logic for a requesting system outside the original sysplex is configured for a serial mode to fail an additional open request for the first data set when the usage counter of the original sysplex is non-zero and to record an error message to a first diagnostics log for the requesting system.