Changing the Limit for Concurrent Mirror Operations

The system allows a maximum of 50 concurrent mirroring operations by default. Mirroring operations include both mirroring and promoting from read-only mirrors to read-write standard volumes. The system parameter that controls this limit is mapr.mirror.concurrent.ops.

For large-scale mirror operations involving many volumes, a script automates the process. For example, if a script queues 100 volumes for mirroring operations, and the mapr.mirror.concurrent.ops limit is set to 50, the mirroring operations start on the first 50 volumes in the queue. As soon as one volume completes, another volume is processed from the queue until all 100 are completed. Since volumes are processed from the queue in first-in first-out (FIFO) order, the script should specify the most critical volumes first.

If you want to process more volumes at a time, you can raise the limit of the mapr.mirror.concurrent.ops parameter. To tune this parameter for maximum efficiency, consider the number of containers per volume. A higher number of containers per volume requires a lower limit than a lower number of containers per volume. To raise the limit to 500 for example, run the following command:

maprcli config save -values {"mapr.mirror.concurrent.ops":"500"}