Chapter 20. Managing Resource Usage

When Red Hat Gluster Storage is deployed on the same machine as other resource intensive software and services, it can be useful to limit the resources that glusterd attempts to use in order to avoid resource contention between processes.

Procedure 20.1. Limiting glusterd resources on RHEL7 based Red Hat Gluster Storage

On Red Hat Gluster Storage 3.2 and higher deployments based on Red Hat Enterprise Linux 7, this can be configured using gdeploy. For more information, see Section 5.1.11, “Limiting Gluster Resources”.
On earlier versions of Red Hat Gluster Storage, it is necessary to manually configure a control group slice for the glusterd service in order to manage glusterd's access to system resources.
  1. Stop all gluster processes
    # systemctl stop glusterd

    Important

    If glusterd crashes, there is no functionality impact to this crash as it occurs during the shutdown. For more information, see Section 24.3, “Resolving glusterd Crash”
  2. Create a service configuration directory for glusterd
    # mkdir /etc/systemd/system/glusterd.service.d
  3. Create a service configuration file
    # echo "[Service]
    CPUAccounting=yes
    Slice=glusterfs.slice" >> /etc/systemd/system/glusterd.service.d/99-cpu.conf
  4. Create a slice file
    The following defines a slice that sets CPUQuota to the recommended value of 400% (four cores).
    # echo "[Slice]
    CPUQuota=400%" >> /etc/systemd/system/glusterfs.slice
    You can alter the percentage to suit your environment by editing the value in the slice file:
    # systemctl set-property glusterfs.slice CPUQuota=value
  5. Restart the system daemon
    # systemctl daemon-reload
  6. Start gluster processes
    # systemctl start glusterd
For more information about configuring resource management on Red Hat Enterprise Linux 7, see the Resource Management Guide: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html-single/Resource_Management_Guide/index.html#sec-What_are_Control_Groups
Resource management works differently on Red Hat Enterprise Linux 6. See the Red Hat Enterprise Linux 6 Resource Management Guide for details: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Resource_Management_Guide/ch-Using_Control_Groups.html

Procedure 20.2. Controlling CPU Usage for a Gluster Daemon

The control-cpu-load script provides a utility to control CPU utilization for any Gluster daemon by using the cgroup framework to configure CPU quota for a process.
  1. Navigate to the scripts folder by using the following command:
    # cd /usr/share/glusterfs/scripts
  2. Determine the PID of the required gluster daemon by using the following command:
    # ps -aef | grep daemon_name
    The output will be in the following format:
    root      1565...output omitted...grep --color=auto daemon_name
    In this output, 1565 represents the PID of the daemon service. PIDs are unlikely to be the same on different systems, or for different instances of the daemon, so ensure that you check for the relevant PID every time you perform this process.
  3. Execute the control-cpu-load script by using the following command:
    # sh control-cpu-load.sh
  4. When the system prompts you with the following input, type the PID of the daemon acquired from the previous step and press Enter:
    [root@XX-XX scripts]# sh control-cpu-load.sh
    Enter gluster daemon pid for which you want to control CPU.
    1565
  5. When the system prompts you with the following input, type y and press Enter:
    If you want to continue the script to attach 1565 with new cgroup_gluster_1565 cgroup Press (y/n)?
  6. When the system prompts the following notification, enter the required quota value to be assigned to the daemon and press Enter:
    Creating child cgroup directory 'cgroup_gluster_1565 cgroup' for daemon_name.service.
    Enter quota value in range [10,100]:
    25
    
    In this example, quota value for the daemon service is set to 25.
    The system displays the following message once the quota value has been successfully set:
    Entered quota value is 25
    Setting 25000 to cpu.cfs_quota_us for gluster_cgroup.
    Tasks are attached successfully specific to 1565 to cgroup_gluster_1565.

Important

Perform this procedure every time the daemon is restarted and has a new daemon PID.

Procedure 20.3. Controlling memory usage for a Gluster daemon

The control-mem script provides a utility to control memory utilization for any Gluster daemon by using the cgroup framework to configure memory limit for a process.
  1. Navigate to the scripts folder by using the following command:
    # cd /usr/share/glusterfs/scripts
  2. Determine the PID of the required gluster daemon by using the following command:
    # ps -aef | grep daemon_name
    The output will be in the following format:
    root      1565     1  0 Feb05 ?        00:09:17 /usr/sbin/glusterfs -s localhost --volfile-id gluster/daemon_name -p /var/run/gluster/daemon_name/daemon_name.pid -l /var/log/glusterfs/daemon_name.log -S /var/run/gluster/ed49b959a0dc9b2185913084e3b2b339.socket --xlator-option *replicate*.node-uuid=13dbfa1e-ebbf-4cee-a1ac-ca6763903c55
      root     16766 14420  0 19:00 pts/0    00:00:00 grep --color=auto daemon_name
    In this output, 1565 represents the PID of the daemon service.
  3. Execute the control-mem script by using the following command:
    # sh control-mem.sh
  4. When the system prompts for the following input, type the PID of the daemon acquired from the previous step and press Enter:
    [root@XX-XX scripts]# sh control-mem.sh
    Enter gluster daemon pid for which you want to control CPU.
    1565
    In this example, 1565 represents the PID of the daemon service. The PID of the daemon services can vary from system to system.
  5. When the system prompts for the following input, type y and press Enter:
    If you want to continue the script to attach daeomon with new cgroup. Press (y/n)?
    The system prompts the following notification:
    Creating child cgroup directory 'cgroup_gluster_1565 cgroup' for daemon_name.service.
  6. When the system prompts for the following input, enter the required memory value to be assigned to the daemon and press Enter:
    Enter Memory value in Mega bytes [100,8000000000000]:
    In this example, the memory value is set to 5000. The system prompts the following message once the memory value has been successfully set:
    Entered memory limit value is 5000.
    Setting 5242880000 to memory.limit_in_bytes for /sys/fs/cgroup/memory/system.slice/daemon_name.service/cgroup_gluster_1565.
    Tasks are attached successfully specific to 1565 to cgroup_gluster_1565.

Important

Perform this procedure every time the daemon is restarted and has a new daemon PID.