Method and apparatus for the on-line reconfiguration of the logical volumes of a data storage system

• US 6,209,059 B1
• Filed: 09/25/1997
• Issued: 03/27/2001
• Est. Priority Date: 09/25/1997
• Status: Expired due to Term

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Fitzgerald, John, Ofer, Erez, Halligan, Kenneth
• Primary Examiner(s): Yoo, Do Hyun
• Assistant Examiner(s): GOODARZI, NASSER MOAZZAMI
• Application Number:
  US08/937,467
• Time in Patent Office: 1,279 Days
• Field of Search: 395/182.05, 711/114, 711/170, 711/173, 714/7
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1096 Parity calculation or recalculation after configuration or reconfiguration of the system
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0632 by initialisation or re-initialisation of storage systems
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A method of dynamically reconfiguring the logical devices in a storage system is provided. The method allows a logical devices to be added, removed, or repositioned without requiring the storage system to be taken off-line. The method includes manipulating the request queues associated with host controllers within the storage system. The request queues associated with each logical device may be repositioned in the request queue memory in order to make room for new logical devices or to take advantage of free space associated with a removed logical device. The storage system communicates with the host computer in order to manage the reconfiguration of the request queues while still providing storage services to the host computer.

Claims

1. A method of dynamic on-line storage system reconfiguration wherein said storage system includes a request queue and wherein said request queue includes a plurality of device queues, one for each storage device, each of the device queues having entries corresponding to each storage device, said method comprising the steps of:

receiving a reconfiguration command;

saving a current configuration of said storage system, said current configuration including a number of storage devices in said storage system and an arrangement of device queues in said request queue;

continuing to operate said storage system according to said current configuration;

reconfiguring the request queue to accommodate a new configuration of said storage system by compressing each device queue to support the number of entries needed for the storage device;

updating said request queue to the new configuration;

operating said storage system in accordance with said new configuration;

based on new configuration parameters, calculating a new device queue size associated with each storage device of said new configuration;

preventing new entries to be placed in the request queue; and

during said preventing step, servicing requests in said request queue until the number of outstanding requests for each of said device queues is less than or equal to a capacity of said new device queue size.