ispmanager 6 lite, pro, host

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CloudLinux limits

CloudLinux limits

CloudLinux allows you to limit user resource usage. It is achieved through LVE and MySQL Governor technologies. LVE can operate both in conjunction with and independently of MySQL Governor.

When used separately, LVE sets server resource limits for all user tasks.

When LVE is used in conjunction with MySQL Governor, database-level limits are applied. MySQL Governor monitors the database server load during set periods of time. If the load persists, MySQL Governor contacts LVE to reduce user process activity to the set limits.

Example

A user is uploading a database backup to ispmanager. To prevent crashes in other users' processes and maintain sufficient database server performance, the administrator is limiting resources using MySQL Governor. The user's task is given a lower priority, takes longer to complete, but completes successfully. Other users' processes are not getting blocked or slowed down.

All limits are specified in the CloudLinux section.

Limits configuration is available for administrator-level accounts or above.

LVE limits

LVE limits apply only to Apache processes when executing PHP or CGI scripts. Dovecot/Exim processes are not subject to limits.

LVE limits will be applied to users if individual settings are not specified. 

  • CPU load limit — the user process limit threshold. Values ​​are expressed as a percentage (%). For example, 100% corresponds to one core being fully loaded.
  • Total number of processes (NPROC) — the user process threshold. The value is expressed in units.
  • Physical memory — the maximum amount of physical memory that can be allocated to processes of a user. The value is expressed in MB, includes shared memory and disk cache.
  • I/O limit — the maximum data throughput for reading and writing data from the disk. The value is expressed in KB/second.
  • LVE concurrent connections (EP) — the maximum number of LVE user processes. The value is expressed in units.

CloudLinux recommendations for LVE limits

 Regular hostingHigh-end hosting
CPU load limit100%200%
Physical memory512 MB1 GB
I/O limit1024 KB/s4096 KB/s
LVE concurrent connections2040
Total number of processes100100

LVE configuration files

Limits are specified in the configuration file at /etc/container/ve.cfg.

Limit parameters:

  • <cpu limit="VALUE"/> — controls the maximum CPU load
  • <nproc limit="VALUE"/> — controls the total number of processes
  • <io limit="VALUE"/> — controls the maximum disk access speed
  • <mem limit="VALUE"/> — controls the physical memory threshold
  • <other maxentryprocs="VALUE"/> — controls the threshold for the number of concurrent LVE connections

MySQL Governor limits

Available in ispmanger pro and ispmanager host.

You can limit resource consumption for different time periods:

  • 1 second
  • 15 seconds
  • 1 minute
  • 5 minutes

This allows users to load the server for a short period, but prevents from loading the server for too long.

To use limits, Enable MySQL Governor and set the following parameters:

  • CPU load — the processor load threshold. The value is expressed as a percentage (%).

    Example

    100% means all cores being fully loaded, 50% means half of the cores being fully loaded, 25% means 25% of the cores being fully loaded, etc.

  • Read — the threshold for the amount of data read from the disk over a specified period of time. The value is expressed in MB/second. Cached data is not included.
  • Write — the threshold for the amount of data written to the disk. The value is expressed in MB/second.

If you want to use unlimited mode, set the value in the fields to -1.

If a user exceeds MySQL Governor thresholds, LVE limits will be applied to the user queries.

To monitor the load, go to the Server resources section.

Differences from ispmanager business

For ispmanager business, the limits apply to periods of: 1 second, 15 seconds, 1 minute, and 15 minutes.

MySQL Governor configuration files

Limits are specified in the configuration file at /etc/container/mysql-governor.xml.

Time period parameters:

  • current — corresponds to a 1-second value
  • short — corresponds to a 15-second value
  • mid — corresponds to a 1-minute value
  • long — corresponds to a 5-minute value

Limit parameters:

  • <limit name="cpu" current="VALUE" short="VALUE" mid="VALUE" long="VALUE" /> — CPU load limit for time periods
  • <limit name="read" current="VALUE" short="VALUE" mid="VALUE" long="VALUE" /> — disk read limit for time periods
  • <limit name="write" current="VALUE" short="VALUE" mid="VALUE" long="VALUE" /> — disk write limit for time periods

MySQL Governor logging

The parameter that controls MySQL Governor limits (top processes) is dbtop.

Information on program operation is written to the following files:

  • /var/log/dbgovernor-error.log — error log for establishing a connection between MySQL Governor and the MySQL database server
  • /var/log/dbgovernor-mysqld.log — MySQL Governor connection log for the MySQL database server
  • /var/log/dbgovernor-restrict.log — load block monitoring log for the MySQL database server
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