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| Full Name | Type | Description |
|---|---|---|
| kafka.server:type=KafkaServer,name=DiskReadBytesTotalDiskReadBytes | 64-bit gauge | The total number of bytes read by the broker process. This includes reads from all disks. It does not include reads that came out of page cache. |
| kafka.server:type=KafkaServer,name=DiskWriteBytesTotalDiskWriteBytes | 64-bit gauge | The total number of bytes written by the broker process. This includes writes from all disks. |
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These metrics will be collected from the /proc/self/io file on Linux. DiskReadBytes TotalDiskReadBytes comes out of the line marked "read_bytes:". DiskWriteBytes TotalDiskWriteBytes comes out of taking the line marked "write_bytes:" and subtracting it from the value in the line marked "cancelled_write_bytes: ". This reflects the fact that write bytes which were cancelled and not performed should not be counted.
The broker will read this file from the /proc filesystem whenever the metric needs to be accessed. We will not re-read the file more than once a millisecond even if the gauge is accessed multiple times during that period.
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