SLM Modes

SLM is automatically enabled during the Parallels Server Bare Metal installation on the server, i.e. you do not have to perform any additional operations to start using this functionality on your server. After the installation, you can manage SLM in one of the following ways:

• Disable SLM on a global basis. In this case no Container on the server will be able to make use of this functionality. To disable SLM, complete the following tasks:
  • Specify no as the value of the SLM parameter in the /etc/vz/vz.conf global configuration file.
  • Reboot the server:

    # shutdown -r now

• Control the SLM mode for a particular Container on the server. The current version of Parallels Server Bare Metal allows you to set one of the following SLM modes for your Container:
  • limited mode . In this mode, the SLM functionality for the corresponding Container is enabled and can be used to control the 'total' and 'low' memory consumption by all Containers on the server, which prevents the memory from being overused and guarantees the reliable performance of the server. At the same time, you can use various UBC parameters to manage particular resources of the Container. If the Container does not have any UBC parameters set, SLM also undertakes the control over the consumption of these resources by this Container. By default, any Container created is functioning in the limited mode . If your Container is working in another mode, you can return it to this mode by executing the pctl set command and passing the --slmmode all option to it.
  • full mode . In this mode, the SLM functionality for the corresponding Container is enabled and can be used to the full extent for managing the amount of memory which can be allocated to and consumed by the Container. Enabling the full mode automatically sets the values of all UBC parameters to unlimited. When functioning in this mode, SLM may significantly improve the resources allocation among individual Containers. For example, it allows you to avoid situations when the memory allocation for some application inside the Container fails although the system has a lot of free resources. The full mode can be set by using the --slmmode slm option with the pctl set command.
  • compatibility mode . In this mode, the SLM functionality for the corresponding Container is disabled and the system resources control management is performed by using UBC parameters only: numproc , numtcpsock , numothersock , vmguarpages , kmemsize , etc. Detailed information on all UBC parameters is provided the Administrator's Guide to Managing UBC Resources guide available at http://www.parallels.com/products/virtuozzo/docs/ . The compatibility mode can be set by using the --slmmode ubc option with the pctl set command.

    Note: You can also enable any of the aforementioned modes by editing the Container configuration file and setting the corresponding value ( all , slm , or ubc , respectively) of the SLM parameter in this file.