Method and apparatus for the on-line reconfiguration of the logical volumes of a data storage system
First Claim
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.
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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.
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Citations
1 Claim
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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:
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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.
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Specification