Installing alternate disk migration

The nimadm command performs a migration in 12 phases.

Each phase can be executed individually using the -P flag. Before performing a migration in phases, you should have a good understanding of the nimadm process. The nimadm phases are as follows:
  1. The master issues the alt_disk_install command to the client, which makes a copy of the rootvg to the target disks (this is Phase 1 of the alt_disk_install process). In this phase, altinst_rootvg (alternate rootvg) is created. If a target mksysb has been specified, the mksysb is used to create a rootvg using local disk caching on the NIM master.
  2. The master runs remote client commands to export all of the /alt_inst file systems to the master. The file systems are exported as read/write with root access to the master. If a target mksysb has been specified, the cache file systems are created based on the from the mksysb.
  3. The master NFS mounts the file systems exported in Phase 2. If a target mskysb has been specified, the mksysb archive is restored into the cache file systems created in Phase 2.
  4. If a premigration script resource has been specified, it is executed at this time.
  5. System configuration files are saved. Initial migration space is calculated and appropriate file system expansions are made. The bos image is restored and the device database is merged (similar to a conventional migration). All of the migration merge methods are executed and some miscellaneous processing takes place.
  6. All system filesets are migrated using installp. Any required RPM images are also installed during this phase.
  7. If a post-migration script resource has been specified, it is executed at this time.
  8. The bosboot command is run to create a client boot image, which is written to the client's boot logical volume (hd5).
  9. All mounts made on the master in phase 3 are removed.
  10. All client exports created in phase 2 are removed.
  11. The alt_disk_install command is called again (phase 3 of alt_disk_install) to make final adjustments and put altinst_rootvg to sleep. The bootlist is set to the target disk (unless the -B flag is used). If an output mksysb has been specified, the cache is archived into a mksysb file, and made a nim mksysb resource.
  12. Cleanup is executed to end the migration. The client is rebooted, if the -r flag is specified.
Note: The nimadm command supports migrating several clients at the same time.