Patent ID: 11874740
Assignee: DELL PRODUCTS L.P.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 15:
16. A non-transitory computer readable medium comprising code stored thereon that, when executed, performs a method comprising:
configuring a stretched volume from two volumes of two data storage systems configured as a cluster, wherein each of the two volumes is included in a different one of the two data storage systems, wherein the two volumes configured as the stretched volume are exposed to a host as a same logical volume having a same first identifier over a plurality of paths from the two data storage systems, wherein the two volumes are configured for bidirectional synchronous replication between the two data storage systems whereby a write directed to the stretched volume received at any one of the two data storage systems is synchronously replicated to the other one of the two data storage systems of the cluster, wherein the two data storage systems include a first data storage system and a second data storage system, wherein the cluster uses a time-to-live (TTL) mechanism by which a preferred one of the two data storage systems communicates permission for continued operation in the cluster to a non-preferred one of the two data storage systems in response to TTL requests from the non-preferred data storage system, and wherein the first data storage system is designated as the non-preferred data storage system and wherein the second data storage system is designated as the preferred data storage system; and
responsive to detecting an occurrence of a trigger condition, triggering first polarization processing for the first data storage system, wherein said first polarization processing includes:
determining that the first data storage system is unhealthy; and
responsive to determining that the first data storage system is unhealthy, performing first processing including:
determining a first intentional time delay due the first data storage system being unhealthy;
determining a second intentional time delay due to the first data storage system being designated as the non-preferred data storage system;
waiting until expiration of the TTL of the first data storage system plus a specified amount of time;
responsive to waiting until expiration of the TTL of the first data storage system plus the specified amount of time, waiting an amount of time equal to the first intentional time delay and the second intentional time delay prior to sending a request to a witness requesting that the first data storage system be declared a polarization winner;
responsive to waiting the amount of time, sending the request to the witness requesting that the first data storage system be declared a polarization winner; and
responsive to said request, receiving a response from the witness, wherein the response indicates whether the first data storage system is the polarization winner selected as a sole surviving system to service I/Os without replicating writes of the stretched volume to the second data storage system, or a polarization loser that is evicted from the cluster and rejects I/Os.