This document is for a development version of Ceph.
Monitoring Ceph iSCSI gateways
Ceph provides a tool for iSCSI gateway environments to monitor performance of exported RADOS Block Device (RBD) images.
gwtop tool is a
top-like tool that displays aggregated
performance metrics of RBD images that are exported to clients over
iSCSI. The metrics are sourced from a Performance Metrics Domain Agent
(PMDA). Information from the Linux-IO target (LIO) PMDA is used to list
each exported RBD image, the connected client, and its associated I/O
A running Ceph iSCSI gateway
root, install the
ceph-iscsi-toolspackage on each iSCSI gateway node:
yum install ceph-iscsi-tools
root, install the performance co-pilot package on each iSCSI gateway node:
yum install pcp
root, install the LIO PMDA package on each iSCSI gateway node:
yum install pcp-pmda-lio
root, enable and start the performance co-pilot service on each iSCSI gateway node:
systemctl enable pmcd systemctl start pmcd
root, register the
cd /var/lib/pcp/pmdas/lio ./Install
gwtop assumes the iSCSI gateway configuration object is
stored in a RADOS object called
gateway.conf in the
This configuration defines the iSCSI gateways to contact for gathering
the performance statistics. This can be overridden by using either the
-c flags. See
gwtop --help for more details.
The LIO configuration determines which type of performance statistics to
extract from performance co-pilot. When
gwtop starts it looks at the
LIO configuration, and if it find user-space disks, then
selects the LIO collector automatically.
Example ``gwtop`` Outputs
gwtop 2/2 Gateways CPU% MIN: 4 MAX: 5 Network Total In: 2M Out: 3M 10:20:00 Capacity: 8G Disks: 8 IOPS: 503 Clients: 1 Ceph: HEALTH_OK OSDs: 3 Pool.Image Src Size iops rMB/s wMB/s Client iscsi.t1703 500M 0 0.00 0.00 iscsi.testme1 500M 0 0.00 0.00 iscsi.testme2 500M 0 0.00 0.00 iscsi.testme3 500M 0 0.00 0.00 iscsi.testme5 500M 0 0.00 0.00 rbd.myhost_1 T 4G 504 1.95 0.00 rh460p(CON) rbd.test_2 1G 0 0.00 0.00 rbd.testme 500M 0 0.00 0.00
In the Client column,
(CON) means the iSCSI initiator (client) is
currently logged into the iSCSI gateway. If
-multi- is displayed,
then multiple clients are mapped to the single RBD image.