I have two questions. 1. I would like to ask about CAS location. current our implementation store content address object in storage tier.However, If we store the CAO in the cache tier, we can get a performance advantage. Do you think we can create CAO in cachetier? or create a separate storage pool for CAS? 2. The results below are performance result for our current implementation. experiment setup: PROXY (inline dedup), WRITEBACK (lazy dedup, target_max_bytes: 50MB), ORIGINAL(without dedup feature and cache tier), fio, 512K block, seq. I/O, single thread One thing to note is that the writeback case is slower than the proxy. We think there are three problems as follows. A. The current implementation creates a fingerprint by reading the entire object when flushing. Therefore, there is a problem that read and write are mixed. B. When client request read, the promote_object function reads the object and writes it back to the cache tier, which also causes a mix of read and write. C. When flushing, the unchanged part is rewritten because flush operation perform per-object based. Do I have something wrong? or Could you give me a suggestion to improve performance? a. Write performance (KB/s) dedup_ratio 0 20 40 60 80 100 PROXY 45586 47804 51120 52844 56167 55302 WRITEBACK 13151 11078 9531 13010 9518 8319 ORIGINAL 121209 124786 122140 121195 122540 132363 b. Read performance (KB/s) dedup_ratio 0 20 40 60 80 100 PROXY 112231 118994 118070 120071 117884 132748 WRITEBACK 34040 29109 19104 26677 24756 21695 ORIGINAL 285482 284398 278063 277989 271793 285094 thanks, Myoungwon Oh -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
