Ceph » RADOS

On Mon, 29 Apr 2019, Alexander Y. Fomichev wrote:

Hi,

I just upgraded from mimic to nautilus(14.2.0) and stumbled upon a strange
"feature".
I tried to increase pg_num for a pool. There was no errors but also no
visible effect:

1. ceph osd pool get foo_pool01 pg_num
   pg_num: 256
2. ceph osd pool set foo_pool01 pg_num 512
   set pool 11 pg_num to 512
3. ceph osd pool get foo_pool01 pg_num
   pg_num: 256

until finally I found that

1. ceph osd require-osd-release nautilus
   solves this problem

Docs are very scarce about "require-osd-release" command. Something like
"Complete the upgrade by disallowing pre-Nautilus OSDs and enabling all new
Nautilus-only functionality:" which gives no clue to understand why pretty
old feature of increasing pg_num dosn't work. Any way I doubt that silently
ignoring user commands is a good idea.
So question is: It is intentional behavior or I hit a bug.

mon sets pg_num_target but encodes with mimic features.