/proc/diskstats: Explanation & Insights

Statistics about disk I/O

/proc/diskstats is a virtual file in the proc file system of a Linux system that provides statistics about disk I/O activity on the system. It is a useful resource for analyzing and troubleshooting issues related to disk performance.

The file is organized as a series of lines, with each line containing information about a particular disk or partition. Each line consists of a series of fields, separated by whitespace.

The fields are as follows:

  • Major number: The major number of the device.
  • Minor number: The minor number of the device.
  • Device name: The name of the device (e.g., sda, sdb, etc.)
  • Reads completed successfully: The number of reads that have been completed successfully.
  • Reads merged: The number of reads that have been merged into a single request.
  • Sectors read: The number of sectors that have been read.
  • Time spent reading (ms): The amount of time (in milliseconds) that has been spent reading.
  • Writes completed: The number of writes that have been completed successfully.
  • Writes merged: The number of writes that have been merged into a single request.
  • Sectors written: The number of sectors that have been written.
  • Time spent writing (ms): The amount of time (in milliseconds) that has been spent writing.
  • I/Os currently in progress: The number of I/O operations that are currently in progress.
  • Time spent doing I/Os (ms): The amount of time (in milliseconds) that has been spent doing I/O operations.
  • Weighted time spent doing I/Os (ms): The amount of time (in milliseconds) that has been spent doing I/O operations, weighted by the time that the I/O operations take.

To read /proc/diskstats, you can use a command-line utility such as cat, less, or more to display the contents of the file. For example:

cat /proc/diskstats

Alternatively, you can use a tool such as awk or sed to parse and extract specific information from the file.

It's also worth noting that some Linux distributions provide utilities such as iostat or vmstat that can be used to display summary statistics about disk and memory usage on the system. These tools can be helpful for identifying trends and patterns in resource usage over time.

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