@Override
  public long getReadOpsCountForProcess() {
    return lastReadOpsCountForProcess;
  }
All data metrics are collected from <b>/proc/</b>.

<p><b>/proc/diskstats</b> is a file in Linux, it contains the running information of the disks,
including device name, read operation count, merged read operation count, write operation count,
merged write operation count etc. This class collects the data periodically and analyzes the
changes in each pieces of data to gain an insight of the disks of status.

<p><b>/proc/[PID]/io</b> is also a file in Linux, it indicates the io status of a specific
process. The content of it contains following items: actual read byte, actual write byte, read
system call count, write system call count, byte attempt to read, byte attempt to write,
cancelled write byte.
iotdb-core/metrics/interface/src/main/java/org/apache/iotdb/metrics/metricsets/disk/LinuxDiskMetricsManager.java