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US 2020/0401546 A1Published application
Lightweight proxy for handling scsi commands in an active array -standby array configuration
AssigneeWestern Digital Technologies, Inc.
InventorVikash Mehta
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Abstract
An apparatus, system, and method are disclosed that service SCSI commands, including SCSI PGR commands in the standby node of a storage system that operates in an Asymmetric Logic Unit Access (ALUA) mode. The apparatus, system, and method service SCSI PGR commands without maintaining peer/proxy port information. The apparatus, system, and method service SCSI commands by forwarding/proxying commands between the active node and standby node, in both directions and use a modified command descriptor block (MCDB) message to conduct the communications between the nodes.
Claims20
An apparatus comprising:
- an active controller configured to:
- operate in an Asymmetric Logic Unit Access (ALUA) mode;
- and
- service Persistent Group Reservation (PGR) Small Computer System Interface (SCSI) commands over an optimized access (OA) path to a host;
- a standby controller configured to:
- operate in the ALUA mode;
- and
- service SCSI PGR commands over a non-optimized access (NOA) path to the host;
- and
- a communication channel between the active controller and the standby controller, the communication channel configured to communicatively couple the active controller and the standby controller such that the standby controller services SCSI PGR commands over the NOA path.
7 more elements
A system comprising:
- a source node configured to:
- service Small Computer System Interface (SCSI) commands from a host;
- and
- be coupled to a first storage device that includes a logical partition;
- a destination node configured to:
- be coupled to a second storage device;
- and
- service SCSI commands from the host;
- a communication channel between the source node and the destination node;
- and
- a migrator configured to migrate the logical partition from the source node to the destination node such that the host maintains storage operations with both the source node and the destination node during migration of the logical partition.
8 more elements
A system comprising:
- a means for directing a source node to operate in an Asymmetric Logic Unit Access (ALUA) mode as an active node, in response to a request to perform a live data migration operation, the source node comprising a first storage device having a logical partition designated as a source logical partition for the live data migration operation;
- a means for directing the source node to service storage commands targeted for the logical partition during the live data migration operation, the storage commands received at the source node, based on where data referenced by the storage command resides during the live data migration operation;
- a means for directing a destination node to operate in ALUA mode as a standby node during the live data migration operation, the destination node comprising a second storage device configured to receive a copy of the logical partition;
- a means for directing the destination node to service storage commands targeted for the logical partition during the live data migration operation, the storage commands received at the destination node, based on where data referenced by the storage command resides during the live data migration operation;
- a means for directing a migrator to initiate the live data migration operation and move data of the logical partition from the first storage device to the second storage device;
- and
- in response to completing migration of data of the logical partition to the second storage device, the means for directing the source node directs the active node to operate in ALUA mode as a standby node and directs the standby node to operate in ALUA mode as an active node.
4 more elements
Dependencies are inferred from the claim text.