Editing UBC primary parameters
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The most important parameters determining the resources available to | The most important parameters determining the resources available to | ||
− | + | Virtual Environment are explained below. The meaning of the parameters | |
− | is illustrated assuming that the | + | is illustrated assuming that the Virtual Environment runs some network |
server applications. | server applications. | ||
== numproc == | == numproc == | ||
− | Maximum number of processes and kernel-level threads allowed for this | + | Maximum number of processes and kernel-level threads allowed for this Virtual Environment. |
Many server applications (like Apache Web server, FTP and mail servers) | Many server applications (like Apache Web server, FTP and mail servers) | ||
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The <code>barrier</code> of this parameter should be set equal to the <code>limit</code>. | The <code>barrier</code> of this parameter should be set equal to the <code>limit</code>. | ||
− | If each | + | If each Virtual Environment has it's own set of IP addresses (which is |
the only way a OpenVZ system can be configured), there are no direct | the only way a OpenVZ system can be configured), there are no direct | ||
limits on the total number of TCP sockets in the system. The number | limits on the total number of TCP sockets in the system. The number | ||
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more memory it needs. | more memory it needs. | ||
− | The amount of memory that | + | The amount of memory that Virtual Environment's applications are |
guaranteed to be able to allocate is specified as the <code>barrier</code> of | guaranteed to be able to allocate is specified as the <code>barrier</code> of | ||
<code>vmguarpages</code> parameter. The current amount of allocated memory space | <code>vmguarpages</code> parameter. The current amount of allocated memory space | ||
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If the current amount of allocated memory space does not exceed the | If the current amount of allocated memory space does not exceed the | ||
guaranteed amount (the <code>barrier</code> of <code>vmguarpages</code>), | guaranteed amount (the <code>barrier</code> of <code>vmguarpages</code>), | ||
− | memory allocations of | + | memory allocations of Virtual Environment's applications always succeed. |
If the current amount of allocated memory space exceeds the guarantee but below | If the current amount of allocated memory space exceeds the guarantee but below | ||
the <code>barrier</code> of <code>privvmpages</code>, allocations may or may not succeed, | the <code>barrier</code> of <code>privvmpages</code>, allocations may or may not succeed, | ||
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made by the applications fail. | made by the applications fail. | ||
The memory allocation guarantee (<code>vmguarpages</code>) is a primary tool for | The memory allocation guarantee (<code>vmguarpages</code>) is a primary tool for | ||
− | controlling the memory available to | + | controlling the memory available to Virtual Environments, because |
it allows administrators to provide Service Level Agreements — agreements | it allows administrators to provide Service Level Agreements — agreements | ||
guaranteeing certain quality of service, certain amount of resources | guaranteeing certain quality of service, certain amount of resources | ||
and general availability of the service. The unit of measurement | and general availability of the service. The unit of measurement | ||
of vmguarpages values is memory pages (4KB on x86 and x86_64 processors). | of vmguarpages values is memory pages (4KB on x86 and x86_64 processors). | ||
− | The total memory allocation guarantees given to | + | The total memory allocation guarantees given to Virtual Environments |
are limited by the physical resources of the computer — the size of RAM | are limited by the physical resources of the computer — the size of RAM | ||
and the swap space — as discussed in [[UBC systemwide configuration]]. | and the swap space — as discussed in [[UBC systemwide configuration]]. | ||
There is a ''pseudo-graphical'' tool - <code>[http://en.dklab.ru/lib/dklab_vzmem/ vzmem]</code> - which allows you to distribute physical memory among all VEs consistently. It shows all physical memory blocks graphically in <code>/etc/vz/conf/MEM-MAP</code> text file and lets you to move these blocks from one VE to another to redistribute the memory. Also you may specify "additional" memory personally for each VE: such memory will be obtained from system's free memory or swap (it is reflected as modifying of <code>privvmpages</code> parameter). | There is a ''pseudo-graphical'' tool - <code>[http://en.dklab.ru/lib/dklab_vzmem/ vzmem]</code> - which allows you to distribute physical memory among all VEs consistently. It shows all physical memory blocks graphically in <code>/etc/vz/conf/MEM-MAP</code> text file and lets you to move these blocks from one VE to another to redistribute the memory. Also you may specify "additional" memory personally for each VE: such memory will be obtained from system's free memory or swap (it is reflected as modifying of <code>privvmpages</code> parameter). |