Dear AIXers

Thanks a ton in advance, I assure another ton later....

What is the benefit of exact mapping when we mirror a VG.
What if we can not mirror a VG with exact mapping, what we lose?

Exact mapping means that mirroring algorithm uses the same physical
partitions on different physical volumes to keep a copy of a LV. So, if
lv00 was created on first 64 PPs of hdisk0, then a copy on hdisk1 will
also be created on forst 64 PPs.

In theory, this will keep both PVs utilization similiar, assuming they
have similiar characteristics.

My opinion? If you use internal server disks only for rootvg, don't
bother.
Use exact mapping only for mirroring heavily utilized, large LVs.