Selecting candidates for demotion from a first asynchronous replication technique to a second asynchronous replication technique

A system comprising:

• one or more processors;
• and
• a memory comprising code stored thereon that, when executed, performs a method comprising:
• configuring a plurality of stretched volumes for asynchronous replication, wherein each of the plurality of stretched volumes is configured from a source volume on a source system and a target volume on a target system, and where writes or data changes to the source volume are asynchronously replicated from the source system to the target system and applied to the target volume, wherein said configuring includes configuring the plurality of stretched volumes to perform asynchronous replication in a first mode using a first replication technique that performs one or more optimizations including a first optimization that uses a write tracking cache of the source system to track locations of each of the plurality of stretched volumes that are written between successive replication-related snapshots of respective source volumes of the plurality of stretched volumes;
• performing asynchronous replication for the plurality of stretched volumes in accordance with the first replication technique;
• and
• monitoring resource consumption of the write tracking cache consumed during asynchronous replication processing in connection with the first replication technique, wherein said monitoring includes:
• determining that a current amount of write tracking cache consumed exceeds a high watermark threshold;
• and
• responsive to determining that the current amount of write tracking cache consumed exceeds a high watermark threshold, performing first processing that selects, in accordance with criteria, one or more of the plurality of stretched volumes for demotion from the first replication mode, that uses the first replication technique, to a second replication mode that uses a second replication technique, wherein the second replication technique does not perform the first optimization and does not use the write tracking cache.

A non-transitory computer-readable media comprising code stored thereon that, when executed, performs a method comprising:

• configuring a plurality of stretched volumes for asynchronous replication, wherein each of the plurality of stretched volumes is configured from a source volume on a source system and a target volume on a target system, and where writes or data changes to the source volume are asynchronously replicated from the source system to the target system and applied to the target volume, wherein said configuring includes configuring the plurality of stretched volumes to perform asynchronous replication in a first mode using a first replication technique that performs one or more optimizations including a first optimization that uses a write tracking cache of the source system to track locations of each of the plurality of stretched volumes that are written between successive replication-related snapshots of respective source volumes of the plurality of stretched volumes;
• performing asynchronous replication for the plurality of stretched volumes in accordance with the first replication technique;
• and
• monitoring resource consumption of the write tracking cache consumed during asynchronous replication processing in connection with the first replication technique, wherein said monitoring includes:
• determining that a current amount of write tracking cache consumed exceeds a high watermark threshold;
• and
• responsive to determining that the current amount of write tracking cache consumed exceeds a high watermark threshold, performing first processing that selects, in accordance with criteria, one or more of the plurality of stretched volumes for demotion from the first replication mode, that uses the first replication technique, to a second replication mode that uses a second replication technique, wherein the second replication technique does not perform the first optimization and does not use the write tracking cache.