Browse Prior Art Database

Error Recovery From Controller Failures in a Virtually Addressed Mass Storage System

IP.com Disclosure Number: IPCOM000085422D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Angstadt, RA: AUTHOR [+3]

Abstract

A virtually addressed mass storage system (MSS) services a plurality of hosts under general direction of a primary host. The mass storage system has an offline controller MSC (mass storage control) for controlling the internal functions of the mass store, and establishing supervisory functions for data storage and retrieval.

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Error Recovery From Controller Failures in a Virtually Addressed Mass Storage System

A virtually addressed mass storage system (MSS) services a plurality of hosts under general direction of a primary host. The mass storage system has an offline controller MSC (mass storage control) for controlling the internal functions of the mass store, and establishing supervisory functions for data storage and retrieval.

A plurality of director staging adapters (DIRSA) data ports 01, 02, 03 provide data communications between selected hosts and any of a plurality of disk storage apparatus arranged in staging drive groups. Intercommunication between the various disk storage units, represented by the small circles, such as 14, 62, etc., is via a plurality of controllers C1-C4.

A given staging drive group of disk storage units, such as consisting of units with addresses 14, 62, A3, is usually through C1.

Disk unit A3 is accessible either by C1 or C2. Disk unit address F1 is accessible only through C2. If C2 fails, as indicated by the hatched area, data stored on disk unit F1 is inaccessible to any of the ports 01, 02, 03 to MSC and, hence, is effectively not in the mass storage system.

In a virtually addressed mass storage system, as indicated in the drawing, a virtual or logical addressing data unit, such as a virtual volume, is stored on a plurality of the disk storage units. Accordingly, disk storage unit F1 may have portions of 30 virtual volumes or more. In an interactive system with which the MSS may be employed, losing such portions of 30 volumes or more can seriously degrade...