Patent ID: 8924675
Filing Date: 2014-12-30
Classification: G06F

Abstract:
1. A method of migrating data for a logical device, comprising: subdividing the logical device into subsections, wherein the logical device is a single logical storage unit (LUN), wherein each of the subsections corresponds to a particular address range of the logical device that is mapped to a physical device containing corresponding data, wherein the subsections of the logical device include at least a first subsection and a second subsection that are identified to achieve load balancing, wherein data of the first subsection is expected to have a higher activity level than data of the second subsection over a time period; copying the data of the first subsection from a first physical device to a second, different, physical device, wherein the data of the first subsection that is copied to the second physical device is scheduled for temporary storage on the second physical device as a working set copy of the data of the first subsection for input/output (I/O) processing for the time period corresponding to the expected higher activity level, wherein the data of the second subsection is maintained indefinitely on the first physical device after copying the data of the first subsection to the second physical device, and wherein, after the copying, the data of the first subsection is present on the first physical device and the working set copy of the data of the first subsection is present on the second physical device; during the time period, servicing received I/O requests for the data of the first subsection using the working set copy of the data of the first subsection present on the second physical device; and after the time period, updating the data for the first subsection present on the first physical device using the working set copy of the data for the first subsection present on the second physical device as modified by any received I/O requests, and thereafter releasing memory used to store the working set copy of the data of the first subsection on the second physical device.