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How to: Identify processes performing high disk I/O wait activity

Release Classification Level DB Platform Categories
All INFO  ALL Performance



How to identify processes performing significantly high amount of disk I/O wait activity?



This KB comes extremely handy when investigating causes of high system CPU core utilization.

One of the causes, besides the network interrupts, can be very high disk I/O wait activity handled by the CPU.

Below is the simple procedure, using iotop utility.

1. Connect to the ScaleArc box using the SSH access.

2. Switch to root user with 'sudo su -' command.

3. Install iotop utility using 'sudo yum install iotop'.

4. Run the utility with 'iotop' command.

5. Find the process performing high I/O disk activity by looking at IO column first. The example shows that journaling process jbd2 spends 2.42% of thread/process time while waiting on I/O.

6. Sort the processes using using Left/Right arrows by available parameteres: TID, PRIO, USER, DISK READ, DISK WRITE, SWAPIN, IO, COMMAND


For more information, refer to the man pages of iotop utility.


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