[lvm-devel] [BUG-REPORT] mirror legs in the same PV with --alloc anywhere

[Alasdair G Kergon]

Well current policies for -m1 with mirrored log:
4 areas required M1 & M2 (data); L1 & L2 (log)

  contiguous - 4 PVs required
  cling - same
  normal  - same
  anywhere - no restriction - 1 PV may be enough.

Suggestion is another policy with requirements:
  1.  L* may share PVs with M*,
  2.  M1 and M2 not on same PV as each other,
  3.  L1 and L2 not on same PV as each other.

And to insert that policy between 'normal' and 'anywhere' in the sequence.

There is a stronger form of 1: 
  1s. L* must share PVs with M* 
but I think we can manage without that for now because people can obtain the same
result with this policy by listing only the PVs concerned on the command line.
Or would it be better to implement 1s+2+3 as the first new policy?

Alasdair