Display Ceph performance counters

The ceph daemon DAEMON_NAME perf schema command outputs the available metrics. Each metric has an associated bit field value type.

Prerequisites

  • A running IBM Storage Ceph cluster.

  • Root-level access to the node.

Procedure

  1. To view the metric’s schema:

    Syntax 

    ceph daemon DAEMON_NAME perf schema
    Note: Run the ceph daemon command from the node running the daemon.

  2. Executing ceph daemon DAEMON_NAME perf schema command from the monitor node:

    Example 

    [ceph: root@host01 /]# ceph daemon mon.host01 perf schema

  3. Executing the ceph daemon DAEMON_NAME perf schema command from the OSD node:

    Example 

    [ceph: root@host01 /]# ceph daemon osd.11 perf schema
Table 1. The bit field value definitions
Bit Meaning

1

Floating point value

2

Unsigned 64-bit integer value

4

Average (Sum + Count)

8

Counter

Each value will have bit 1 or 2 set to indicate the type, either a floating point or an integer value. When bit 4 is set, there will be two values to read, a sum and a count. When bit 8 is set, the average for the previous interval would be the sum delta, since the previous read, divided by the count delta. Alternatively, dividing the values outright would provide the lifetime average value. Typically these are used to measure latencies, the number of requests and a sum of request latencies. Some bit values are combined, for example 5, 6 and 10. A bit value of 5 is a combination of bit 1 and bit 4. This means the average will be a floating point value. A bit value of 6 is a combination of bit 2 and bit 4. This means the average value will be an integer. A bit value of 10 is a combination of bit 2 and bit 8. This means the counter value will be an integer value.