My current settings are:
mds advanced mds_beacon_grace 15.000000
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.
On 14/12/2020 22:33, Patrick Donnelly wrote:
> On Mon, Dec 7, 2020 at 12:06 PM Patrick Donnelly <pdonnell(a)redhat.com> wrote:
>> Hi Dan & Janek,
>>
>> On Sat, Dec 5, 2020 at 6:26 AM Dan van der Ster <dan(a)vanderster.com>
wrote:
>>> My understanding is that the recall thresholds (see my list below)
>>> should be scaled proportionally. OTOH, I haven't played with the decay
>>> rates (and don't know if there's any significant value to tuning
>>> those).
>> I haven't gone through this thread yet but I want to note for those
>> reading that we do now have documentation (thanks for the frequent
>> pokes Janek!) for the recall configurations:
>>
>>
https://docs.ceph.com/en/latest/cephfs/cache-configuration/#mds-recall
>>
>> Please let us know if it's missing information or if something could
>> be more clear.
> I also now have a PR open for updating the defaults based on these and
> other discussions:
https://github.com/ceph/ceph/pull/38574
>
> Feedback welcome.
>