On Ceph Memory Management

Monitor and OSD daemons

First we will see the output of ceph orch ps command.

ceph orch ps output from experiment-ceph

Only two types of daemons have memory limits: mon and osd. We will see the same output from two other Ceph clusters.

ceph orch ps output from toy-ceph

ceph orch ps output from new25-ceph

These memory limits are governed by four properties. Their values can retrieved using the following commands.

sudo ceph config get mon mon_memory_target  # in bytes
sudo ceph config get mon mon_memory_autotune
sudo ceph config get osd osd_memory_target  # in bytes
sudo ceph config get osd osd_memory_target_autotune

We will collect all the values from the three clusters.

Memory related values from the three Ceph clusters

Some Questions from the Table

Memory Limits and Memory Targets