Emc IP Holding Company LLC

Ashwin Ramkrishna Tidke

Venkatesh Doddamane Nagaraj

Kurumurthy Gokam

Amit Pundalik Anchi

Saurabh Tripathi

Poonam Garg

Hanish Kandangattu Hariharan

A host device is configured to obtain a default timeout value of the host device for the submission of an input-output (IO) operation to a storage system and to determine a first timeout value that is less than the default timeout value. The host device is further configured to submit the IO operation to the storage system along a first path using the first timeout value and to determine that the submission of the IO operation along the first path has timed out. The host device is further configured to determine a second timeout value that is greater than the first timeout value and to submit the IO operation to the storage system along a second path using the second timeout value.

Fast multipath failover

An apparatus in one embodiment comprises a host device that is configured to communicate over a network with at least one storage system comprising a source logical storage volume and a target logical storage volume. Responsive to a reboot of the host device during a migration of a plurality of chunks of data from the source logical storage volume to the target logical storage volume, the host device is configured to determine, based at least in part on an entry of a copy migration journal, the entry corresponding to a given chunk of the plurality of chunks, that the migration of the given chunk was in progress prior to the reboot. Responsive to determining that the migration of the given chunk was in progress prior to the reboot, the host device is configured to resume the migration of the plurality of chunks from the given chunk.

Migration resumption using journals

A host computer dispatches storage I/O operations to a storage array by, in an I/O dispatch context, (i) identifying an I-T-L nexus based on a minimum-weight I-T nexus and a logical device of a storage I/O operation, (ii) dispatching the I/O on the identified I-T-L nexus, and (iii) updating a dispatch weight for the minimum-weight I-T nexus and logical device. In an I/O completion context, a completion weight is updated for an I-T nexus and logical device of a completed I/O. A background process is performed regularly for selecting the minimum-weight I-T nexus, including (a) for each I-T nexus, calculating a current weight value as a sum of difference values for all logical devices, each being the difference between the dispatch weight and the completion weight for the I-T nexus and logical device, and (b) selecting the I-T nexus having a minimum current weight value as the minimum-weight I-T nexus.

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Bengaluru, India

Ashwin Ramkrishna Tidke