IBM Support

IBM i File Sizes are Different after Migration

Troubleshooting


Problem

File or other object sizes are different after migration to new disks.

Cause

Object sizes can be different after migrating to new disk. The sizes can be larger or smaller depending on what you are migrating from and too. This can be due to the number of Disk Pages used to store the object. Pages only go down to 4kb chunks of size. Depending on how they are spread out among the different sets of disks then they may have different sizes. When restoring to new disks, there is usually more contiguous storage available which require less fragmented chunks of storage. The type of disk, disk protection type and sets, and total number of disk units in the RAID or mirror set will also become a factor in file size difference.
If you are also migrating to a new release, then these objects are converted to be compatible with the new release and may have additional fields or other data associated with the object.

Resolving The Problem

File sizes can vary after migration from kilobytes to a few megabytes. No additional actions are needed. However, if the sizes vary by tens or hundreds of megabytes or especially gigabytes, then these larger size differences could be caused by a different factor that should be investigated further such as comparing the number of rows, fields, version/release/level of the objects.

Document Location

Worldwide

[{"Type":"MASTER","Line of Business":{"code":"LOB57","label":"Power"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SWG60","label":"IBM i"},"ARM Category":[{"code":"a8m0z0000000CH0AAM","label":"Internal LIC and Partitions"}],"ARM Case Number":"","Platform":[{"code":"PF012","label":"IBM i"}],"Version":"All Versions"}]

Document Information

Modified date:
04 January 2023

UID

ibm16852323