[ceph-users] PG number per OSD

Dear Ceph folks, As the capacity of one HDD (OSD) is growing bigger and bigger, e.g. from 6TB up to 18TB or even more, should the number of PG per OSD increase as well, e.g. for 200 to 800. As far as i know, the capacity of each PG should be set smaller for performance reasons due to the existence of PG locks, thus shall i set the number of PGs per OSD to 1000 or even 2000? what is the actual reason for not setting the number of PGs per OSD? Is there any practical limations on the number of PGs? thanks a lot, Samuel huxiaoyu(a)horebdata.cn