[PATCH docs 0/1] pveceph: document FastEC (allow_ec_optimizations)

[Kefu Chai <k.chai@proxmox.com>]

Ceph Tentacle's allow_ec_optimizations flag is a nice win for RBD-on-EC
workloads, though it's a one-way switch and the upstream code is still
settling in - seven post-release fixes landed in 20.2.1 (which we don't
ship yet).

I did think about adding a pveceph CLI flag or a web UI checkbox, but
pveceph doesn't expose other per-pool flags like compression_mode or
noscrub either, and operators are expected to use the Ceph CLI directly
for those. Treating allow_ec_optimizations as a special case felt
inconsistent. The web UI also doesn't have an EC pool creation form at
all, so a checkbox would need a much bigger UI change to have anywhere
to live.

So for now, just documenting it feels like the right call: what it does,
what the preconditions are, the one-way-switch caveat, and the Ceph CLI
commands to enable it. If the pattern for per-pool flags changes down the
road, pveceph can grow a knob then.

Kefu Chai (1):
  pveceph: document FastEC (allow_ec_optimizations) on erasure coded
    pools

 pveceph.adoc | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)

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