C100DBA Server Administration Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  db.currentOp()

  Why it's wrong here

  db.currentOp() shows currently running operations and can help identify long-running queries, but it does not provide historical or aggregated disk I/O per collection. It is a point-in-time view and may miss I/O patterns that occur between samples. It is not the best tool for identifying collections with the most disk activity.

• ✓

  mongotop

  Why this is correct

  mongotop reports per-collection read and write activity over time. It shows how much time each collection spends on reads and writes, making it ideal for identifying which collections are causing high disk I/O. By running mongotop during peak hours, the DBA can pinpoint the collections that are the biggest contributors to disk load.

• ✗

  db.serverStatus()

  Why it's wrong here

  db.serverStatus() provides a wealth of server-wide metrics, including memory, connections, and some I/O statistics, but it does not break down disk activity by collection. It is useful for overall health but not for identifying which specific collections are causing high disk I/O. The DBA needs per-collection granularity.

• ✗

  db.collection.stats()

  Why it's wrong here

  db.collection.stats() returns statistics about a specific collection, such as size, index sizes, and document counts. It does not show real-time read/write activity or I/O per collection. It is useful for capacity planning but not for identifying which collections are actively causing disk I/O during peak hours.