These general commands for Ceph are helpful for obtaining information pertinent to troubleshooting issues.
As a reference, the Ceph commands below are run from a ceph-mon node. Certain commands will work on different systems. For example, the rbd command can be used on the worker nodes if specifying the proper key.
cephadm ls to retrieve the systemd_unit on the node for the process, then utilize journalctl to dump the logsceph log last [<num:int>] [debug|info|sec|warn|error] [*|cluster|audit|cephadm]
cephadm logs [-h] [--fsid FSID] --name <systemd_unit>Print the status of the Ceph cluster with the following command:
ceph -s
Example output:
cluster:
id: 5f3b4031-d6c0-4118-94c0-bffd90b534eb
health: HEALTH_OK <<-- WARN/ERROR/CRITICAL are other states
services:
mon: 3 daemons, quorum ncn-s001,ncn-s002,ncn-s003 (age 20h) <<-- Should have quorum and ideally an odd number of mon nodes
mgr: ncn-s003(active, since 9d), standbys: ncn-s001, ncn-s002 <<-- The watchdog for the cluster
mds: cephfs:1 {0=ncn-s002=up:active} 2 up:standby <<-- Filesystem service
osd: 18 osds: 18 up (since 20h), 18 in (since 9d) <<-- Data devices: 1 OSD = 1 hard drive designated for Ceph
rgw: 3 daemons active (ncn-s001.rgw0, ncn-s002.rgw0, ncn-s003.rgw0) <<-- Object storage
data: <<-- Health stats related to the above services
pools: 11 pools, 220 pgs
objects: 825.66k objects, 942 GiB
usage: 2.0 TiB used, 61 TiB / 63 TiB avail
pgs: 220 active+clean
io:
client: 2.5 KiB/s rd, 13 MiB/s wr, 2 op/s rd, 1.27k op/s wr
The -w option can be used to watch the cluster.
Check the OSD status, weight, and location.
ceph osd tree
Example output:
ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
-1 62.85938 root default
-7 20.95312 host ncn-s001
1 ssd 3.49219 osd.1 up 1.00000 1.00000
5 ssd 3.49219 osd.5 up 1.00000 1.00000
6 ssd 3.49219 osd.6 up 1.00000 1.00000
7 ssd 3.49219 osd.7 up 1.00000 1.00000
8 ssd 3.49219 osd.8 up 1.00000 1.00000
9 ssd 3.49219 osd.9 up 1.00000 1.00000
-5 20.95312 host ncn-s002
2 ssd 3.49219 osd.2 up 1.00000 1.00000
4 ssd 3.49219 osd.4 up 1.00000 1.00000
10 ssd 3.49219 osd.10 up 1.00000 1.00000
11 ssd 3.49219 osd.11 up 1.00000 1.00000
12 ssd 3.49219 osd.12 up 1.00000 1.00000
13 ssd 3.49219 osd.13 up 1.00000 1.00000
-3 20.95312 host ncn-s003
0 ssd 3.49219 osd.0 up 1.00000 1.00000
3 ssd 3.49219 osd.3 up 1.00000 1.00000
14 ssd 3.49219 osd.14 up 1.00000 1.00000
15 ssd 3.49219 osd.15 up 1.00000 1.00000
16 ssd 3.49219 osd.16 up 1.00000 1.00000
17 ssd 3.49219 osd.17 up 1.00000 1.00000
The following command shows the storage utilization of the cluster and pools:
ceph df
Example output:
RAW STORAGE:
CLASS SIZE AVAIL USED RAW USED %RAW USED
kube 27 GiB 15 GiB 9.2 GiB 12 GiB 45.25
smf 57 GiB 30 GiB 24 GiB 27 GiB 48.09
TOTAL 84 GiB 44 GiB 34 GiB 40 GiB 47.18
POOLS:
POOL ID STORED OBJECTS USED %USED MAX AVAIL
cephfs_data 1 0 B 0 0 B 0 13 GiB
cephfs_metadata 2 2.2 KiB 22 1.5 MiB 0 13 GiB
.rgw.root 3 1.2 KiB 4 768 KiB 0 13 GiB
defaults.rgw.buckets.data 4 0 B 0 0 B 0 13 GiB
default.rgw.control 5 0 B 8 0 B 0 13 GiB
defaults.rgw.buckets.index 6 0 B 0 0 B 0 13 GiB
default.rgw.meta 7 0 B 0 0 B 0 13 GiB
default.rgw.log 8 0 B 175 0 B 0 13 GiB
kube 10 3.1 GiB 799 9.2 GiB 40.64 4.5 GiB
smf 11 8.1 GiB 2.11k 24 GiB 47.71 8.9 GiB
Show the utilization of the OSDs with the following command. This is very helpful to see if the data is not balanced across OSDs, which can create hotspots.
ceph osd df
Example output:
ID CLASS WEIGHT REWEIGHT SIZE RAW USE DATA OMAP META AVAIL %USE VAR PGS STATUS
1 kube 0.00879 1.00000 9 GiB 4.1 GiB 3.1 GiB 0 B 1 GiB 4.9 GiB 45.25 0.96 99 up
4 smf 0.01859 1.00000 19 GiB 9.1 GiB 8.1 GiB 0 B 1 GiB 9.9 GiB 48.09 1.02 141 up
0 kube 0.00879 1.00000 9 GiB 4.1 GiB 3.1 GiB 0 B 1 GiB 4.9 GiB 45.25 0.96 93 up
3 smf 0.01859 1.00000 19 GiB 9.1 GiB 8.1 GiB 0 B 1 GiB 9.9 GiB 48.09 1.02 147 up
2 kube 0.00879 1.00000 9 GiB 4.1 GiB 3.1 GiB 0 B 1 GiB 4.9 GiB 45.25 0.96 100 up
5 smf 0.01859 1.00000 19 GiB 9.1 GiB 8.1 GiB 0 B 1 GiB 9.9 GiB 48.09 1.02 140 up
TOTAL 84 GiB 40 GiB 34 GiB 0 B 6 GiB 44 GiB 47.18
MIN/MAX VAR: 0.96/1.02 STDDEV: 1.51
Use the following command to obtain information about a single OSD using the OSD number. For example, osd.0 would be an OSD number.
ceph osd find OSD.ID
Example output:
{
"osd": 1,
"addrs": {
"addrvec": [
{
"type": "v1",
"addr": "10.248.2.127:6800",
"nonce": 4966
}
]
},
"osd_fsid": "9d41f723-e86f-4b98-b1e7-12c0f5f15546",
"host": "ceph-1",
"crush_location": {
"host": "ceph-1",
"root": "default"
}
}
List the storage pools with the following commands:
ceph osd lspools
Example output:
1 cephfs_data
2 cephfs_metadata
3 .rgw.root
4 defaults.rgw.buckets.data
5 default.rgw.control
6 defaults.rgw.buckets.index
7 default.rgw.meta
8 default.rgw.log
10 kube
11 smf