Dynamically adjusting write pacing by calculating a pacing level and then delaying writes for a first channel command word (CCW) based on pacing level

摘要

For dynamically adjusting write pacing, a calculation module calculates an interval as a maximum threshold for a primary volume divided by a first maximum pacing level for a first importance level. The calculation module further calculates a first pacing level as a number of record sets that have not been mirrored to a secondary volume divided by the interval. The first pacing level is set to the first maximum pacing level if the first pacing level is greater than the first maximum pacing level. The calculation module also selects a first pacing delay associated with the first pacing level from a delay table. A pacing module delays writes for a first channel command word writing to the primary volume by the first pacing delay.

主权项

1. A method for dynamically adjusting write pacing comprising:
calculating, by use of a processor, an interval INT as a maximum threshold T for a primary volume of a primary storage subsystem divided by a first maximum pacing level MP1 for a first importance level, wherein INT=T/MP1 and writes to the primary volume are stored as record sets in a cache and mirrored to a secondary volume of a secondary storage subsystem; calculating a first pacing level as a number of record sets that have not been mirrored to the secondary volume divided by the interval, wherein the first pacing level is set to the first maximum pacing level if the first pacing level is greater than the first maximum pacing level; selecting a first pacing delay associated with the first pacing level from a delay table; and delaying writes for a first channel command word (CCW) writing to the primary volume by the first pacing delay.