[ceph-users] RDB Performance / High IOWaits.

8 Jun 2020

      Greetings,

I'm using ceph (14.2.2); in conjunction with Proxmox. Currently I'm just doing tests and ran into an issue relating to high I/O waits. Just to give a little bit of a background, specifically relating to my current ceph configurations; we have 6 nodes, each consisting of 2 osds (each node has 2x Intel SSDSC2KG019T8) OSD Type is bluestore. Global configurations (at least as shown on the proxmox interface) is as follows:

[global]
	 auth_client_required = xxxx
	 auth_cluster_required = xxxx
	 auth_service_required = xxxx
	 cluster_network = 10.125.0.0/24
	 fsid = f64d2a67-98c3-4dbc-abfd-906ea7aaf314
	 mon_allow_pool_delete = true
	 mon_host = 10.125.0.101 10.125.0.102 10.125.0.103 10.125.0.105 10.125.0.106 10.125.0.104
	 osd_pool_default_min_size = 2
	 osd_pool_default_size = 3
	 public_network = 10.125.0.0/24

[client]
	keyring = /etc/pve/priv/$cluster.$name.keyring

If I'm missing any relevant information relating to my ceph setup (I'm still learning this), please let me know.

Each node consists of 2x Xeon E5-2660 v3. Where I ran into high I/O waits is when running a VM. VM is a mysql replication server (using 8 cores), and is performing mostly writes. When trying to narrow down, it was pointing to disk writes. The only thing I'm seeing in the ceph logs are the following:

2020-06-08 02:43:01.062082 mgr.node01 (mgr.2914449) 8009571 : cluster [DBG] pgmap v8009574: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 2.4 MiB/s wr, 274 op/s
2020-06-08 02:43:03.063137 mgr.node01 (mgr.2914449) 8009572 : cluster [DBG] pgmap v8009575: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 0 B/s rd, 3.0 MiB/s wr, 380 op/s
2020-06-08 02:43:05.064125 mgr.node01 (mgr.2914449) 8009573 : cluster [DBG] pgmap v8009576: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 0 B/s rd, 2.9 MiB/s wr, 332 op/s
2020-06-08 02:43:07.065373 mgr.node01 (mgr.2914449) 8009574 : cluster [DBG] pgmap v8009577: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 0 B/s rd, 2.7 MiB/s wr, 313 op/s
2020-06-08 02:43:09.066210 mgr.node01 (mgr.2914449) 8009575 : cluster [DBG] pgmap v8009578: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 341 B/s rd, 2.9 MiB/s wr, 350 op/s
2020-06-08 02:43:11.066913 mgr.node01 (mgr.2914449) 8009576 : cluster [DBG] pgmap v8009579: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 341 B/s rd, 3.1 MiB/s wr, 346 op/s
2020-06-08 02:43:13.067926 mgr.node01 (mgr.2914449) 8009577 : cluster [DBG] pgmap v8009580: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 341 B/s rd, 3.5 MiB/s wr, 408 op/s
2020-06-08 02:43:15.068834 mgr.node01 (mgr.2914449) 8009578 : cluster [DBG] pgmap v8009581: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 341 B/s rd, 3.0 MiB/s wr, 320 op/s
2020-06-08 02:43:17.069627 mgr.node01 (mgr.2914449) 8009579 : cluster [DBG] pgmap v8009582: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 341 B/s rd, 2.5 MiB/s wr, 285 op/s
2020-06-08 02:43:19.070507 mgr.node01 (mgr.2914449) 8009580 : cluster [DBG] pgmap v8009583: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 341 B/s rd, 3.0 MiB/s wr, 349 op/s
2020-06-08 02:43:21.071241 mgr.node01 (mgr.2914449) 8009581 : cluster [DBG] pgmap v8009584: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 0 B/s rd, 2.8 MiB/s wr, 319 op/s
2020-06-08 02:43:23.072286 mgr.node01 (mgr.2914449) 8009582 : cluster [DBG] pgmap v8009585: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 2.7 MiB/s wr, 329 op/s
2020-06-08 02:43:25.073369 mgr.node01 (mgr.2914449) 8009583 : cluster [DBG] pgmap v8009586: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 2.8 MiB/s wr, 304 op/s
2020-06-08 02:43:27.074315 mgr.node01 (mgr.2914449) 8009584 : cluster [DBG] pgmap v8009587: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 2.2 MiB/s wr, 262 op/s
2020-06-08 02:43:29.075284 mgr.node01 (mgr.2914449) 8009585 : cluster [DBG] pgmap v8009588: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 682 B/s rd, 2.9 MiB/s wr, 342 op/s
2020-06-08 02:43:31.076180 mgr.node01 (mgr.2914449) 8009586 : cluster [DBG] pgmap v8009589: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 682 B/s rd, 2.4 MiB/s wr, 269 op/s
2020-06-08 02:43:33.077523 mgr.node01 (mgr.2914449) 8009587 : cluster [DBG] pgmap v8009590: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 682 B/s rd, 3.4 MiB/s wr, 389 op/s
2020-06-08 02:43:35.078543 mgr.node01 (mgr.2914449) 8009588 : cluster [DBG] pgmap v8009591: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 682 B/s rd, 3.1 MiB/s wr, 344 op/s
2020-06-08 02:43:37.079428 mgr.node01 (mgr.2914449) 8009589 : cluster [DBG] pgmap v8009592: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 682 B/s rd, 3.0 MiB/s wr, 334 op/s
2020-06-08 02:43:39.080419 mgr.node01 (mgr.2914449) 8009590 : cluster [DBG] pgmap v8009593: 512 pgs: 512 active+clean; 246 GiB data, 712 GiB used, 20 TiB / 21 TiB avail; 682 B/s rd, 3.3 MiB/s wr, 377 op/s

I'm not sure what could be causing high I/O waits; or whether this is an issue relating to my ceph configurations. Any suggestions would be appreciated/ or if you need any additional information, let me know what you need and I'll post them.

Thank you.

[ceph-users] RDB Performance / High IOWaits.

jameslipski＠protonmail.com