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diff --git a/doc/rbd/iscsi-monitoring.rst b/doc/rbd/iscsi-monitoring.rst new file mode 100644 index 000000000..da94bad87 --- /dev/null +++ b/doc/rbd/iscsi-monitoring.rst @@ -0,0 +1,85 @@ +------------------------------ +Monitoring Ceph iSCSI gateways +------------------------------ + +Ceph provides a tool for iSCSI gateway environments +to monitor performance of exported RADOS Block Device (RBD) images. + +The ``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 +metrics. + +**Requirements:** + +- A running Ceph iSCSI gateway + +**Installing:** + +#. As ``root``, install the ``ceph-iscsi-tools`` package on each iSCSI + gateway node: + + :: + + # yum install ceph-iscsi-tools + +#. As ``root``, install the performance co-pilot package on each iSCSI + gateway node: + + :: + + # yum install pcp + +#. As ``root``, install the LIO PMDA package on each iSCSI gateway node: + + :: + + # yum install pcp-pmda-lio + +#. As ``root``, enable and start the performance co-pilot service on + each iSCSI gateway node: + + :: + + # systemctl enable pmcd + # systemctl start pmcd + +#. As ``root``, register the ``pcp-pmda-lio`` agent: + + :: + + cd /var/lib/pcp/pmdas/lio + ./Install + +By default, ``gwtop`` assumes the iSCSI gateway configuration object is +stored in a RADOS object called ``gateway.conf`` in the ``rbd`` pool. +This configuration defines the iSCSI gateways to contact for gathering +the performance statistics. This can be overridden by using either the +``-g`` or ``-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 ``gwtop`` +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. |