Performing asynchronous discard scans with staging and destaging operations

摘要

A controller receives a request to perform staging or destaging operations with respect to an area of a cache. A determination is made as to whether one or more discard scans are being performed or queued for the area of the cache. In response to determining that one or more discard scans are being performed or queued for the area of the cache, the controller avoids satisfying the request to perform the staging or the destaging operations or a read hit with respect to the area of the cache.

主权项

1. A method, comprising:
maintaining a plurality of logical subsystems, wherein each logical subsystem stores a plurality of volumes; receiving, by a controller, a request to perform staging operations with respect to an area of a cache; in response to determining that one or more discard scans are being performed or queued for a volume, performing: in response to determining from discard task control blocks that the staging operations are not for tracks in a range of tracks being discarded via the discard scans, satisfying the request to perform the staging operations; and in response to determining from the discard task control blocks that the staging operations are for tracks in the range of tracks being discarded via the discard scans, bypassing the cache for stages, and directly stage from one or more disk drives.