US 2019/0163577 A1Published application

Device reservation state preservation in data mirroring

AssigneeInternational Business Machines Corporation

InventorsScott B. Compton, Matthew R. Craig, Clint A. Hardy, Matthew J. Kalos, Carol S. Mellgren, John G. Thompson

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Abstract

One general aspect of device reservation state preservation in accordance with the present description, provides for an intermediate reservation state, referred to herein as a “peer” reservation state, which may be maintained by a storage controller in the event of a total loss of communication connectivity to the reserving host so long as a peer or partner storage controller of a mirror relationship still has communication connectivity to the host. The peer reservation state as used herein, is a reservation state intermediate between a full reservation state for a device, and a fully released state in which a reservation of the device has been completely released. Other features and aspects may be realized, depending upon the particular application.

Claims18

Dependent claims

A computer program product for use with at least one host, a primary data storage system, the primary data storage system having a primary storage controller and a primary storage drive controlled by the primary storage controller, the primary storage drive having a plurality of primary devices configured to store data, and at least one secondary data storage system. each secondary data storage system having a secondary storage controller and a secondary storage drive controlled by the secondary storage controller, the secondary storage drive having a plurality of secondary devices configured to store data, wherein the computer program product comprises a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor of a host to cause processor operations, the processor operations comprising:

receiving by device reservation logic of a secondary storage controller of the secondary data storage system, a propagated reservation request to reserve on behalf of a first host, a secondary device controlled by the secondary storage controller for exclusive use by the first host for input/output (I/O) data requests wherein if the propagated reservation request is granted, other hosts are excluded from use of the secondary device for I/O data requests;
in response to the propagated reservation request, determining by host connection monitoring logic of the secondary storage controller as to whether the secondary storage controller has communication connectivity with the first host;
in response to a determination that the secondary storage controller lacks communication connectivity with the first host, granting by reservation state selection logic of the secondary storage controller, the propagated reservation request as a peer reservation of the secondary device on behalf of the first host, in a peer reservation state;
and
in response to a determination that the secondary storage controller has communication connectivity with the first host, granting by reservation state selection logic of the secondary storage controller, the propagated reservation request as a full reservation of the secondary device on behalf of the first host, in a full reservation state.

2 more elements

A method, comprising:

receiving by device reservation logic of a secondary storage controller of a secondary data storage system, a propagated reservation request to reserve on behalf of a first host, a secondary device controlled by the secondary storage controller for exclusive use by the first host for input/output (I/O) data requests wherein if the propagated reservation request is granted, other hosts are excluded from use of the secondary device for I/O data requests;
in response to the propagated reservation request, determining by host connection monitoring logic of the secondary storage controller as to whether the secondary storage controller has communication connectivity with the first host;
in response to a determination that the secondary storage controller lacks communication connectivity with the first host, granting by reservation state selection logic of the secondary storage controller, the propagated reservation request as a peer reservation of the secondary device on behalf of the first host, in a peer reservation state;
and
in response to a determination that the secondary storage controller has communication connectivity with the first host, granting by reservation state selection logic of the secondary storage controller, the propagated reservation request as a full reservation of the secondary device on behalf of the first host, in a full reservation state.

2 more elements

A system for use with at least one host, comprising:

a primary data storage system, the primary data storage system having a primary storage controller and a primary storage drive controlled by the primary storage controller, the primary storage drive having a plurality of primary devices configured to store data;
and
at least one secondary data storage system. each secondary data storage system having a secondary storage controller and a secondary storage drive controlled by the secondary storage controller, the secondary storage drive having a plurality of secondary devices configured to store data;
wherein the secondary storage controller includes:
device reservation logic configured to receive a propagated reservation request to reserve on behalf of a first host, a secondary device controlled by the secondary storage controller for exclusive use by the first host for input/output (I/O) data requests wherein if the propagated reservation request is granted, other hosts are excluded from use of the secondary device for I/O data requests;
host connection monitoring logic configured to, in response to the propagated reservation request, determine whether the secondary storage controller has communication connectivity with the first host;
and
reservation state selection logic configured to, in response to a determination that the secondary storage controller lacks communication connectivity with the first host, grant the propagated reservation request as a peer reservation of the secondary device on behalf of the first host, in a peer reservation state, and in response to a determination that the secondary storage controller has communication connectivity with the first host, grant the propagated reservation request as a full reservation of the secondary device on behalf of the first host, in a full reservation state.

5 more elements

Dependencies are inferred from the claim text.