RHCSA Rapid Track

Instructions

1. Log in to servera as the student user.

   [student@workstation ~]$ ssh student@servera
   ...output omitted...
   [student@servera ~]$

2. Verify that the tuned package is installed, enabled, and started.

   1. Verify that the tuned package is installed.

      [student@servera ~]$ dnf list tuned
      ...output omitted...
      Installed Packages
      tuned.noarch              2.18.0-1.el9                 @System

   2. Verify that the service is enabled.

      [student@servera ~]$ systemctl is-enabled tuned
      enabled

   3. Verify that the service is currently running.

      [student@servera ~] systemctl is-active tuned
      active

3. List the available tuning profiles and identify the active profile.

   [student@servera ~]$ sudo tuned-adm list
   [sudo] password for student: student
   Available profiles:
   - accelerator-performance     - Throughput performance based tuning with disabled higher latency STOP states
   - balanced                    - General non-specialized tuned profile
   - desktop                     - Optimize for the desktop use-case
   - hpc-compute                 - Optimize for HPC compute workloads
   - intel-sst                   - Configure for Intel Speed Select Base Frequency
   - latency-performance         - Optimize for deterministic performance at the cost of increased power consumption
   - network-latency             - Optimize for deterministic performance at the cost of increased power consumption, focused on low latency network performance
   - network-throughput          - Optimize for streaming network throughput, generally only necessary on older CPUs or 40G+ networks
   - optimize-serial-console     - Optimize for serial console use.
   - powersave                   - Optimize for low power consumption
   - throughput-performance      - Broadly applicable tuning that provides excellent performance across a variety of common server workloads
   - virtual-guest               - Optimize for running inside a virtual guest
   - virtual-host                - Optimize for running KVM guests
   Current active profile: virtual-guest

4. Review the tuned.conf configuration file for the current active profile, virtual-guest. You can find the tuned.conf configuration file in the /usr/lib/tuned/virtual-guest directory. The virtual-guest tuning profile is based on the throughput-performance profile, but it sets different values for the vm.dirty_ratio and vm.swappiness parameters. Verify that the virtual-guest tuning profile applies these values on your system.

   1. Review the virtual-guest configuration file in the /usr/lib/tuned/virtual-guest directory. Verify the values for the vm.dirty_ratio and vm.swappiness parameters.

      [student@servera ~]$ cat /usr/lib/tuned/virtual-guest/tuned.conf
      #
      # tuned configuration
      #
      
      [main]
      summary=Optimize for running inside a virtual guest
      include=throughput-performance
      
      [sysctl]
      # If a workload mostly uses anonymous memory and it hits this limit, the entire
      # working set is buffered for I/O, and any more write buffering would require
      # swapping, so it's time to throttle writes until I/O can catch up.  Workloads
      # that mostly use file mappings may be able to use even higher values.
      #
      # The generator of dirty data starts writeback at this percentage (system default
      # is 20%)
      vm.dirty_ratio = 30
      
      # Filesystem I/O is usually much more efficient than swapping, so try to keep
      # swapping low.  It's usually safe to go even lower than this on systems with
      # server-grade storage.
      vm.swappiness = 30

   2. Verify that the tuning profile applies these values on your system.

      [student@servera ~]$ sysctl vm.dirty_ratio
      vm.dirty_ratio = 30
      [student@servera ~]$ sysctl vm.swappiness
      vm.swappiness = 30

5. Review the tuned.conf configuration file for the virtual-guest parent's tuning profile, throughput-performance. You can find it in the /usr/lib/tuned/throughput-performance directory. Notice that the throughput-performance tuning profile sets a different value for the vm.dirty_ratio and vm.swappiness parameters, although the virtual-guest profile overwrites them. Verify that the virtual-guest tuning profile applies the value for the vm.dirty_background_ratio parameter, which it inherits from the throughput-performance profile.

   1. Review the throughput-performance configuration file in the /usr/lib/tuned/throughput-performance directory. Verify the values for the vm.dirty_ratio, vm.swappiness, and vm.dirty_background_ratio parameters.

      [student@servera ~]$ cat /usr/lib/tuned/throughput-performance/tuned.conf
      #
      # tuned configuration
      #
      
      [main]
      summary=Broadly applicable tuning that provides excellent performance across a variety of common server workloads
      
      ...output omitted...
      
      [sysctl]
      # If a workload mostly uses anonymous memory and it hits this limit, the entire
      # working set is buffered for I/O, and any more write buffering would require
      # swapping, so it's time to throttle writes until I/O can catch up.  Workloads
      # that mostly use file mappings may be able to use even higher values.
      #
      # The generator of dirty data starts writeback at this percentage (system default
      # is 20%)
      vm.dirty_ratio = 40
      
      # Start background writeback (via writeback threads) at this percentage (system
      # default is 10%)
      vm.dirty_background_ratio = 10
      
      # PID allocation wrap value.  When the kernel's next PID value
      # reaches this value, it wraps back to a minimum PID value.
      # PIDs of value pid_max or larger are not allocated.
      #
      # A suggested value for pid_max is 1024 * <# of cpu cores/threads in system>
      # e.g., a box with 32 cpus, the default of 32768 is reasonable, for 64 cpus,
      # 65536, for 4096 cpus, 4194304 (which is the upper limit possible).
      #kernel.pid_max = 65536
      
      # The swappiness parameter controls the tendency of the kernel to move
      # processes out of physical memory and onto the swap disk.
      # 0 tells the kernel to avoid swapping processes out of physical memory
      # for as long as possible
      # 100 tells the kernel to aggressively swap processes out of physical memory
      # and move them to swap cache
      vm.swappiness=10
      
      ...output omitted...

   2. Verify that the virtual-guest tuning profile applies the inherited vm.dirty_background_ratio parameter.

      [student@servera ~]$ sysctl vm.dirty_background_ratio
      vm.dirty_background_ratio = 10

6. Change the current active tuning profile to throughput-performance, and then confirm the results. Verify that the vm.dirty_ratio and vm.swappiness parameters change to the values in the throughput-performance configuration file.

   1. Change the current active tuning profile.

      [student@servera ~]$ sudo tuned-adm profile throughput-performance

   2. Confirm that throughput-performance is the active tuning profile.

      [student@servera ~]$ sudo tuned-adm active
      Current active profile: throughput-performance

   3. Verify the values for the vm.dirty_ratio and vm.swappiness parameters.

      [student@servera ~]$ sysctl vm.dirty_ratio
      vm.dirty_ratio = 40
      [student@servera ~]$ sysctl vm.swappiness
      vm.swappiness = 10

7. Return to the workstation machine as the student user.

   [student@servera ~]$ exit
   logout
   Connection to servera closed.
   [student@workstation ~]$