Ceph : MON logging "_set_cache_ratios Cache kv ratio (1) must be in range [0,<1.0]." and "register_cache_with_pcm Cache ratios for pcm could not be set."

Solution Verified - Updated -

Issue

The Ceph logs are reporting the following error repeatedly:

May 17 09:03:50 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:50.709 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452497 _set_cache_ratios Cache kv ratio (1) must be in range [0,<1.0].
May 17 09:03:50 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:50.709 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452497 register_cache_with_pcm Cache ratios for pcm could not be set. Review the kv (rocksdb) and mon_memory_target sizes.
May 17 09:03:51 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:51.792 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452498 _set_cache_ratios Cache kv ratio (1) must be in range [0,<1.0].
May 17 09:03:51 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:51.792 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452498 register_cache_with_pcm Cache ratios for pcm could not be set. Review the kv (rocksdb) and mon_memory_target sizes.
May 17 09:03:52 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:52.847 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452499 _set_cache_ratios Cache kv ratio (1) must be in range [0,<1.0].
May 17 09:03:52 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:52.847 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452499 register_cache_with_pcm Cache ratios for pcm could not be set. Review the kv (rocksdb) and mon_memory_target sizes.
May 17 09:03:53 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:53.996 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452500 _set_cache_ratios Cache kv ratio (1) must be in range [0,<1.0].
May 17 09:03:53 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:53.996 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452500 register_cache_with_pcm Cache ratios for pcm could not be set. Review the kv (rocksdb) and mon_memory_target sizes.
May 17 09:03:54 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:54.852 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452501 _set_cache_ratios Cache kv ratio (1) must be in range [0,<1.0].
May 17 09:03:54 tvhpmc1-pmon003 ceph-mon[3256545]: 2021-05-17 09:03:54.852 7f9d74559700 -1 mon.tvhpmc1-pmon003@2(peon).osd e452501 register_cache_with_pcm Cache ratios for pcm could not be set. Review the kv (rocksdb) and mon_memory_target sizes.

Breaking down the 2 log messages, which are repeating, we have this:

_set_cache_ratios Cache kv ratio (1) must be in range [0,<1.0].
register_cache_with_pcm Cache ratios for pcm could not be set.
Review the kv (rocksdb) and mon_memory_target sizes.

Environment

Red Hat Ceph Storage (RHCS) 4.x
Red Hat Ceph Storage (RHCS) 5.x
Red Hat Ceph Storage (RHCS) 6.x
Red Hat Ceph Storage (RHCS) 7.x

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