Today, when CSM starts, it assigns objects statically to concurrency slots on target devices. While this offers good performance during the first half of an Object Copy session, with enough data streams assigned to each target device, later only a subset of available concurrency slots are used per target device. This is caused by objects waiting for their target slot to become available and sequencing of objects. Also target devices become idle and fail to unlock. This can be changed using ForceUnlockOfUnusedDevices=1. The overall result is relatively slow Object Copy performance at the end second half of an Object Copy session causing possible causing damage to the target device (in case of tape drives).
Please change Copy Session Manager (CSM), which coordinates every Object Copy session, to have a dynamic queue for objects. It should allocate objects dynamically, deallocate no longer required source and target devices early to optimize device availability to other sessions, throughput and reduce media usage.
Consistent Object Copy performance during the whole Object Copy Session with hundreds or thousands of objects. Prevent high performance tape drives to go into start-stop mode causing damage to the drive.
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