Dell Products Inc.

Emc IP Holding Company LLC

Eran Banin

Leonid Ravich

Ahia Lieber

Inna Reznik

Omer Margolin

Techniques for avoiding race conditions in high availability (HA) storage systems that employ disk array enclosures (DAEs). The techniques include receiving a notification of an input/output (IO) error from a storage node, in which the IO error occurs subsequent to the storage node issuing, to a first DAE controller, an IO operation to access data at a logical address of a storage device. The techniques further include, in response to the notification of the IO error, issuing, over an out-of-band channel, a flush command to the first DAE controller, causing data stored in cache memory of the first DAE controller to be written to the storage device, and receiving, over the out-of-band channel, an acknowledgement of completion of the flush operation from the first DAE controller. The techniques further include sending a notification of the completion of the flush operation to the storage node.

Smart disk array enclosure race avoidance in high availability storage systems

Techniques for providing a framework for handling execution of HA flows in an active-active storage node configuration. The techniques include receiving notifications of functional statuses of processes and/or equipment associated with storage nodes in the active-active configuration, making determinations regarding how to address HA events occurring on the processes and/or equipment associated with the storage nodes based on the received notifications, and, in response to a request to execute an HA flow for a respective HA event, determining whether to refuse the request to execute the HA flow, service the request to execute the HA flow, abort one or more HA flows in execution, and/or postpone execution of the HA flow to a later time based on one or more dependencies defining conditions for the HA flow. In this way, mutual interference of HA flows or other process threads in the active-active configuration can be reduced or eliminated.

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Tel Aviv, Israel

Eran Banin