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The following error message occurred while creating a mirrored logical volume:
# mklv -c 2 -t jfs2 datavg01 10 0516-1814 lcreatelv: Mirror pools must be defined for each copy when strict mirror pools are enabled. 0516-822 mklv: Unable to create logical volume. #
The reason for this is that the mirror pool strictness is set for the volume group. The article Mirror Pools: Understanding Mirror Pool Strictness examines and explains this in more detail.
The attempt to create an unmirrored LV in a VG with mirror pools results in the following error:
# mklv -t jfs2 -p copy1=DC1 datavg01 10 0516-1829 mklv: Every mirror pool must contain a copy of the logical volume. 0516-822 mklv: Unable to create logical volume. #
The cause is the VG‘s Mirror Pool Strictness attribute, which is set to ‘super-strict‘. The article Mirror Pools: Understanding Mirror Pool Strictness examines the importance of Mirror Pool Strictness using examples.
Many IT environments operate their systems in more than one data center. In order not to have any data loss in the event of a failure of an entire data center, the data is mirrored between 2 or more data centers. The mirroring can be realized by the storage (storage based mirroring) or by a volume manager (LVM in the case of AIX) on the server (host based mirroring). In the article Mirror Pools: An Introduction we look at mirroring using AIX Logical Volume Manager and Mirror Pools. The aim is to show how the correct mirroring of logical volumes can be implemented with the help of mirror pools. In larger environments with many physical volumes, maintaining correct mirroring without mirror pools is difficult and a challenge for the administrator.