[ceph-users] Does it make sense to have separate HDD based DB/WAL partition

Dear Ceph folks, I am faced with a special use Ceph scenario, where no SSD is available. Three node Ceph cluster, each with 14 HDDs, no SSD. In this case, should i create a separate DB/WAL partition for each OSD on a HDD? and if yes, how big the partition? Which is the best in terms of performance, with a separate DB/WAL partition, or without? Thanks a lot, samuel huxiaoyu(a)horebdata.cn