Comment 12 for bug 1639691

so now that isa-l-cauchy is available this issue we should consider what Swift can do when you have isa-l-rs-vand policy with > 4 parity frags that is not acknowledged as pre-existing...

I would support a change that would require such policies to be deprecated - then something in the release notes:

  * you must immediately deprecate isa-l-rs-vand policies with >4 parity or your swift won't start
  * you should migrate data out of them
  * you may upgrade liberasurecode/pyeclib and create isa-l-rs-cauchy policies with >4 parity

Some openstack policy on upgrades probably says that we can't merge a fix that require a config change to upgrade - but my better senses says preventing the proliferation of the risk of data loss is a reasonable exception. I'd feel like a real piece of work if someone ended up *creating* such a policy just because it's "only a warning".