My current settings are:
mds advanced mds_beacon_grace 15.000000
True. I might as well remove it completely, it's an artefact of earlier experiments.
This should be a global setting. It is used by the mons and mdss.
mds basic mds_cache_memory_limit 4294967296 mds advanced mds_cache_trim_threshold 393216 global advanced mds_export_ephemeral_distributed true mds advanced mds_recall_global_max_decay_threshold 393216 mds advanced mds_recall_max_caps 30000 mds advanced mds_recall_max_decay_threshold 98304 mds advanced mds_recall_warning_threshold 196608 global advanced mon_compact_on_start true
I haven't had any noticeable slow downs or crashes in a while with 3 active MDS and 3 hot standbys. Thanks for sharing the settings that worked for you.