Data backup copying with delayed directory updating and reduced numbers of DASD accesses at a back up site using a log structured array data storage
US5555371A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 1994 |
| Grant date | Sep 10, 1996 |
| Priority date | — |
| Expiry date | Jul 18, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/2066
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Primary and secondary data processing systems are coupled via a communication system. Data storage in both systems is provided by a log structured array (LSA) system that stores data in compressed form. Each time data are updated within LSA, the updated data are stored in a data storage location different from the original data. Selected data recorded in a primary data storage of the primary system is remote dual copied to the secondary system for congruent storage in a secondary data storage, such as for disaster recovery purposes. The primary systems creates a remote copying session. Within such remote copying session, a series of "pending write update" sessions are ESTABLISHED. All data updated within each pending write update session is a consistency group of data. Within each pending write update session update data are retentively stored in both the primary and secondary systems (such as in a non-volatile cache). Addressability of such update data within a pending write update session is through separate pending write directories. The main (primary and secondary) directory for data is not updated such that all original (not updated) data are addressable. A COMMIT command term…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.