Accessing data between the original rootvg and the new alternate disk
You can initiate data access between the original rootvg and the new alternate disk.
A volume group "wake-up" can be accomplished, on the non-booted volume group. The "wake-up" puts the volume group in a post alt_disk_install Phase 1 state. For example, the /alt_inst file system is then mounted.
The volume group that experiences the "wake-up" is renamed altinst_rootvg. When data access is no longer needed, the volume group can be "put to sleep."
For more information on the command flags to "wake-up" and "put to sleep", see the alt_rootvg_op man page. Once the alternate disk or rootvg is mounted, file access is the same as for any mounted file system.
- The running operating system's version must be greater than or
equal to the version of the volume group that undergoes the "wake-up."
This might mean that it is necessary to boot from the altinst_rootvg
and "wake-up" the old_rootvg.
This limitation is caused by a journaled file system (JFS) log entry incompatibility. It is possible to "wake-up" a volume group that contains a more recent version, but the volume group cannot have ever been the system rootvg. If this was true, the volume group would have made JFS log entries that could not be interpreted by an older version rootvg, when the volume group was experiencing a "wake-up."
The alt_disk_install command does not allow a "wake-up" to occur on a volume group with a more recent version, unless the FORCE environment variable is set to yes.
- The volume group that experiences a "wake-up" must be "put to sleep" before it can be booted and used as the rootvg.
Attention: If a FORCE "wake-up" is attempted on a volume group that contains a more recent version of the running operating system, and the "waking" volume group has been a system rootvg, errors occur.