Hello Eugen. I read all of your MDS related topics and thank you so much for your effort on this. There is not much information and I couldn't find a MDS tuning guide at all. It seems that you are the correct person to discuss mds debugging and tuning. Do you have any documents or may I learn what is the proper way to debug MDS and clients ? Which debug logs will guide me to understand the limitations and will help to tune according to the data flow? While searching, I find this: https://lists.ceph.io/hyperkitty/list/ceph-users@xxxxxxx/thread/YO4SGL4DJQ6EKUBUIHKTFSW72ZJ3XLZS/ quote:"A user running VSCodium, keeping 15k caps open.. the opportunistic caps recall eventually starts recalling those but the (el7 kernel) client won't release them. Stopping Codium seems to be the only way to release." Because of this I think I also need to play around with the client side too. My main goal is increasing the speed and reducing the latency and I wonder if these ideas are correct or not: - Maybe I need to increase client side cache size because via each client, multiple users request a lot of objects and clearly the client_cache_size=16 default is not enough. - Maybe I need to increase client side maximum cache limit for object "client_oc_max_objects=1000 to 10000" and data "client_oc_size=200mi to 400mi" - The client cache cleaning threshold is not aggressive enough to keep the free cache size in the desired range. I need to make it aggressive but this should not reduce speed and increase latency. mds_cache_memory_limit=4gi to 16gi client_oc_max_objects=1000 to 10000 client_oc_size=200mi to 400mi client_permissions=false #to reduce latency. client_cache_size=16 to 128 What do you think? _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
 |