Method for managing volume groups considering storage tiers

A method for managing a tiered storage system, the tiered storage system comprising a plurality of tier positions and a plurality of logical devices, each logical device being associated with a tier position, the method comprising:

• defining a plurality of migration groups, each migration group comprising two or more of the logical devices;
• for each migration group, determining a reference tier position based on the tier positions of its constituent logical devices;
• for each migration group, determining relative position for each of its constituent logical devices, the relative position being determined based on the reference tier position of the migration group and on the tier position of the constituent logical device;
• moving a first migration group, comprising:
• determining a new reference tier position;
• for each logical device comprising the first migration group, determining a new tier position based on the new reference tier position and on its relative position, wherein if the new tier position exceeds the minimum tier position, then the new tier position is set equal to the minimum tier position, wherein if the new tier position exceeds the maximum tier position, then the new tier position is set equal to the maximum tier position, wherein a logical device associated with the new tier position is selected as a corresponding target device;
• and
• migrating data in each logical device comprising the first migration group to its corresponding target device.

A tiered storage system comprising:

• a plurality of physical devices;
• a plurality of logical devices defined among the physical devices;
• the logical devices organized into a plurality of tier positions, wherein each logical device is associated with one of the tier positions;
• and
• a tier management component operative to:
• define a migration group comprising a plurality of first logical devices;
• and
• move the migration group to a different tier position, including for each first logical device, migrating its data to a second logical device having a different tier position,
• wherein data in the first logical devices are migrated to a plurality of second logical devices,
• wherein the relative tier positions among the second logical devices is the same as the relative tier positions among the first logical devices.

A tiered storage system comprising:

• a plurality of storage subsystems, each storage subsystem having an interface that presents its storage logical devices, the storage subsystem thereby providing a plurality of logical devices;
• a plurality of tier positions, each logical device being associated with one of the tier positions;
• a first migration group, the first migration group comprising a plurality of first logical devices;
• a reference tier position associated with the first migration group, the reference tier position being determined based on the tier positions of the first logical devices;
• and
• a management component operative to receive information indicative of a new reference tier position and in response to receiving the information to migrate data in the first logical devices to corresponding second logical devices, wherein the tier position of each second logical device is determined based on the new reference tier position and on the tier position of its corresponding first logical device, wherein relative tier positions among the second logical devices are the same as relative tier positions among the first logical devices.