Applications for non-disruptively moving data between logical disk regions in a data storage system

1. A method for a system manager in a data storage system to move data from source logical disk (LD) regions to target LD regions, the data storage system providing a virtual volume to a host device, the virtual volume being initially mapped to the source LD regions in one or more source logical disks, the source LD regions being mapped to physical storage regions in one or more physical storage devices, the method comprising:

evaluating if moving data in the virtual volume from the source LD regions to the target LD regions would create excessive load on the physical storage devices associated with the source and the target LD regions so that the data storage system appears offline to the host device;

when said moving would not create excessive load, moving data in the virtual volume from the source LD regions to the target LD regions;

flushing dirty cache to the physical storage devices;

determining if said flushing dirty cache is taking longer than a time limit so that the data storage system appears offline to the host device; and

when said flushing dirty cache is not taking longer than the time limit, updating a mapping of the virtual volume from the source LD regions to the target LD regions.

2. The method of claim 1 , wherein prior to said evaluating the method further comprising:

receiving a command from a user of the data storage system to change a RAID type of the virtual volume;

creating one or more target logical disks with a new RAID type; and

determining moves necessary to move data in the source LD regions to the target LD regions in the one or more target logical disks.

3. The method of claim 1 , wherein prior to said evaluating the method further comprising:

receiving a command from a user of the data storage system to change at least one of a layout and a performance of the virtual volume;

creating one or more target logical disks with a new layout; and

determining moves necessary to move data in the source LD regions to the target LD regions in the one or more target logical disks.

4. The method of claim 3 , wherein the new layout includes at least one of new radial placements of data on tracks of disk platters of the physical storage devices, a new distribution of the target LD regions over a new number of the physical storage devices, a new distribution of the target LD regions over a new type of the physical storage device, and a new distribution of the target LD regions over new physical storage devices coupled to different controller nodes.

5. The method of claim 1 , wherein prior to said evaluating the method further comprising:

receiving a command from a user of the data storage system to consolidate space in the virtual volume; and

determining moves necessary to move unused LD regions of the virtual volume to ends of the one or more source logical disks.

6. The method of claim 5 , further comprising truncating the unused LD regions from the ends of the one or more source logical disks to free the unused LD region.

7. The method of claim 1 , wherein prior to said evaluating the method further comprising:

receiving a command from a user of the data storage system to consolidate space in a group of virtual volumes; and

determining moves necessary to move unused LD regions of the virtual volumes to ends of the one or more source logical disks.

8. The method of claim 7 , wherein said moving data in the virtual volume further comprising moving the unused LD regions into a minimum number of logical disks to form at least one empty source logical disk consisting entirely of unused LD regions.

9. The method of claim 8 , further comprising deleting the one empty source logical disk to free the unused LD region.