From mboxrd@z Thu Jan 1 00:00:00 1970 From: Somnath Roy Subject: Severe performance degradation with jewel rbd image Date: Wed, 25 May 2016 20:48:29 +0000 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Return-path: Received: from mail-bl2on0078.outbound.protection.outlook.com ([65.55.169.78]:1056 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751427AbcEYUsd convert rfc822-to-8bit (ORCPT ); Wed, 25 May 2016 16:48:33 -0400 Content-Language: en-US Sender: ceph-devel-owner@vger.kernel.org List-ID: To: "ceph-devel@vger.kernel.org" Hi Mark/Josh, As I mentioned in the performance meeting today , if we create rbd image with default 'rbd create' command in jewel , the individual image performance for 4k RW is not scaling up well. But, multiple of rbd images running in parallel aggregated throughput is scaling. For the same QD and numjob combination, image created with image format 1 (and with hammer like rbd_default_features = 3) is producing *16X* more performance. I did some digging and here is my findings. Setup: -------- 32 osds (all SSD) over 4 nodes. Pool size = 2 , min_size = 1. root@stormeap-1:~# ceph -s cluster db0febf1-d2b0-4f8d-8f20-43731c134763 health HEALTH_WARN noscrub,nodeep-scrub,sortbitwise flag(s) set monmap e1: 1 mons at {a=10.60.194.10:6789/0} election epoch 5, quorum 0 a osdmap e139: 32 osds: 32 up, 32 in flags noscrub,nodeep-scrub,sortbitwise pgmap v20532: 2500 pgs, 1 pools, 7421 GB data, 1855 kobjects 14850 GB used, 208 TB / 223 TB avail 2500 active+clean IO profile : Fio rbd with QD 128 and numjob = 10 rbd cache is disabled. Result: -------- root@stormeap-1:~# rbd info recovery_test/rbd_degradation rbd image 'rbd_degradation': size 1953 GB in 500000 objects order 22 (4096 kB objects) block_name_prefix: rb.0.5f5f.6b8b4567 format: 1 On the above image with format 1 it is giving *~102K iops* root@stormeap-1:~# rbd info recovery_test/rbd_degradation_with_hammer_features rbd image 'rbd_degradation_with_hammer_features': size 195 GB in 50000 objects order 22 (4096 kB objects) block_name_prefix: rbd_data.5f8d6b8b4567 format: 2 features: layering flags: On the above image with hammer rbd features on , it is giving *~105K iops* root@stormeap-1:~# rbd info recovery_test/rbd_degradation_with_7 rbd image 'rbd_degradation_with_7': size 195 GB in 50000 objects order 22 (4096 kB objects) block_name_prefix: rbd_data.5fd86b8b4567 format: 2 features: layering, exclusive-lock flags: On the above image with feature 7 (exclusive lock feature on) , it is giving *~8K iops*...So, >12X degradation Tried with single numjob and QD = 128 , performance bumped up till ~40K..Further increasing QD , performance is not going up. root@stormeap-1:~# rbd info recovery_test/rbd_degradation_with_15 rbd image 'rbd_degradation_with_15': size 195 GB in 50000 objects order 22 (4096 kB objects) block_name_prefix: rbd_data.5fab6b8b4567 format: 2 features: layering, exclusive-lock, object-map flags: On the above image with feature 15 (exclusive lock, object map feature on) , it is giving *~8K iops*...So, >12X degradation Tried with single numjob and QD = 128 , performance bumped up till ~40K..Further increasing QD , performance is not going up. root@stormeap-1:~# rbd info recovery_test/ceph_recovery_img_1 rbd image 'ceph_recovery_img_1': size 4882 GB in 1250000 objects order 22 (4096 kB objects) block_name_prefix: rbd_data.371b6b8b4567 format: 2 features: layering, exclusive-lock, object-map, fast-diff, deep-flatten flags: On the above image with feature 61 (Jewel default) , it is giving *~6K iops*...So, *>16X* degradation Tried with single numjob and QD = 128 , performance bumped up till ~35K..Further increasing QD , performance is not going up. Summary : ------------ 1. It seems exclusive lock feature is degrading performance. 2. It is degrading a bit further on enabling fast-diff, deep-flatten Let me know if you need more information on this. Thanks & Regards Somnath PLEASE NOTE: The information contained in this electronic mail message is intended only for the use of the designated recipient(s) named above. If the reader of this message is not the intended recipient, you are hereby notified that you have received this message in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify the sender by telephone or e-mail (as shown above) immediately and destroy any and all copies of this message in your possession (whether hard copies or electronically stored copies).