Method and system for maintaining concurrent data access during device upgrade
US5701429A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 1996 |
| Grant date | Dec 23, 1997 |
| Priority date | — |
| Expiry date | Aug 16, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0689
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system and method for changing the number of logical volumes in a drawer in a rack in a direct access storage device subsystem is disclosed. The method and system are able to change the number of logical volumes without disrupting access to the other logical volumes in the rack. Channel connection addresses, which are logical volume addresses as known by the CPUs, are freed by removing the old drawer and then are mused. If the new drawer has more logical volumes than the old drawer, the next unused channel connection addresses are used with the new drawer. In a subsystem having a storage controller for providing control for a plurality of direct access storage devices, the logical volumes are spread across multiple physical devices. The storage controller maintains configuration data for the entire subsystem in redundant, non-volatile storage locations reserved specifically for its use. Each logical volume address for the rack is set by the drawer location and the logical sequence of the volumes within the drawer. As drawers are installed, the control unit sequentially assigns the volume addresses for the control unit and the channel connection addresses for the CPUs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.