A Storage migrations Naturally, customers would like to do storage migration in a PowerHA cluster without  disruption to their operations. This is often possible, but not always.  This appendix discusses the following use cases: This is the simplest use case. Correct use of systems facilities allows you to do nondisruptive  storage migration. The basic idea is to add the new disks to an existing volume group (VG),  create a new mirror of the VG on the new disks, and then remove the old disks from the VG.  There are three cases to consider: A new disk or disks can be added to rootvg with the  extendvg  command. A new mirror of  rootvg can be made with the  mirrorvg  command. After completion, the existing disks can  be evacuated with the  rmlvcopy  command, and those disks removed from the VG with  the  reducevg  command. For rootvg’s that contain only a single disk,  replacepv  can be a  more convenient way of performing this operation. There are two important steps that must be performed for rootvg after you complete this  operation: The administrator must check the man pages for the  mirrorvg ,  rmlvcopy , and  reducevg to check the documented restrictions. These restrictions are not expected to apply to the  common run of rootvg configurations, but a quick check in advance can avoid a problem  later. ' Copyright IBM Corp. 2 019. All rights reserved. 477 a. Run  savebase  to update the boot image. b. Run  bootlist  to indicate that the new disks are to be used for the next boot operation. 1. rootvg GLYPH<SM590000> “The new storage cannot be brought online along with the existing storage” on page 478 GLYPH<SM590000> “The new storage can be brought online along with the existing storage” The new storage can be brought online along with the existing  storage