Virtual Storage Point-in-Time Copy for Core Dump Availability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Computer systems face availability issues due to snapshot image creation for error diagnosis, which puts the system in a non-dispatchable state and can lead to time-outs, as existing methods do not effectively manage virtual storage copies without disrupting system operations.
Innovation Solution
The method involves creating a point-in-time copy of virtual storage by marking pages with a protection bit to prevent modifications, allowing for a core dump process using a secondary virtual storage that is referenced via a real storage processor, enabling instant virtual copying and maintaining system availability during error handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a snapshot image of working memory is taken for error diagnosis, then error diagnosis capability is improved, but the system enters a non-dispatchable state causing time-outs
Solution Approach 1:
The system creates a point-in-time copy of virtual storage pages before the core dump process begins. By pre-capturing the state of virtual storage pages and storing them in real storage with protection bits, the system prepares the necessary diagnostic data in advance, allowing the core dump to proceed without blocking application programs and avoiding system time-outs
Solution Approach 2:
The invention creates a copy of virtual storage pages in real storage that can be used for core dump operations. This copying mechanism allows the diagnostic data to be extracted from a static copy rather than requiring the system to halt normal operations, thus maintaining system availability while enabling error diagnosis
2Loss of information
If virtual storage pages are copied during system operation, then diagnostic data is captured, but system operations are disrupted
Solution Approach 1:
The system marks virtual storage pages with protection bits before copying, identifying which pages need to be captured for diagnostic purposes. This preliminary marking allows the core dump process to selectively copy only necessary pages without interrupting normal system operations, as the copying occurs from a stable, pre-identified set of pages
Solution Approach 2:
The invention introduces protection bits as an intermediary mechanism between virtual storage and the core dump process. These bits serve as markers that enable the system to identify and copy diagnostic pages without requiring system-wide halts, thus capturing diagnostic information while maintaining operational continuity
Data Source
AI summary
A method includes copying a first virtual storage by making, a point-in-time copy of a first page content stored in a first structure by creating a second page content in a second structure, the second page content pointing to actual data pointed to by the first page content, storing the second page content in the second data structure, marking the first page content in the first structure with a bit, copying the virtual page in the event the first page content in the first structure is marked with the bit, storing the copied virtual page in a second virtual storage, altering the second page content to point to the stored virtual page, and using the second virtual storage to perform the core dump process, wherein the second virtual storage is referenced via the second page content stored in the real storage.