Hello, I noticed a couple unanswered questions on this topic from a while back. It seems, however, worth asking whether adjusting either or both of the subject attributes could improve performance with large HDD OSDs (mine are 12TB SAS). In the previous posts on this topic the writers indicated that they had experimented with increasing either or both of osd_op_num_shards and osd_op_num_threads_per_shard and had seen performance improvement. Like myself, the writers wondering about any limitations or pitfalls relating to such adjustments. Since I would rather not take chances with a 500TB production cluster I am asking for guidance from this list. BTW, my cluster is currently running Nautilus 14.2.6 (stock Debian packages). Thank you. -Dave -- Dave Hall Binghamton University kdhall(a)binghamton.edu