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New [[Download/kernel/rhel6|RHEL6-based OpenVZ]] kernel has a new memory management model, which supersedes [[UBC|User beancounters]]. It is called '''VSwap'''.
Now you can set two primary parameters: <code>physpages</code> and <code>swappages</code>, while all the other beancounters become secondary.
* '''physpages'''
: This parameter limits the physical memory (RAM) available to processes inside a container.
: The <code>barrier</code> is ignored, and the <code>limit</code> sets the limit.
: Currently the user memory and the page cache are accounted into <code>physpages</code>.
* '''swappages'''
: This parameter limits the amount of swap space which can be used for processes inside a container.
: The <code>barrier</code> is ignored, and the <code>limit</code> sets the limit.
The sum of physpages.limit and swappages.limit limits the maximum amount
of allocated memory which can be used by a container. When physpages limit
is reached, memory pages belonging to the container are pushed out to
so called virtual swap (''vswap''). The difference between normal swap
and vswap is that with vswap no actual disk I/O usually occurs. Instead,
a container is artificially slowed down, to emulate the effect of the real
swapping. Actual swap out occurs only if there is a global memory shortage
on the system.
[[Category: UBC]]
Now you can set two primary parameters: <code>physpages</code> and <code>swappages</code>, while all the other beancounters become secondary.
* '''physpages'''
: This parameter limits the physical memory (RAM) available to processes inside a container.
: The <code>barrier</code> is ignored, and the <code>limit</code> sets the limit.
: Currently the user memory and the page cache are accounted into <code>physpages</code>.
* '''swappages'''
: This parameter limits the amount of swap space which can be used for processes inside a container.
: The <code>barrier</code> is ignored, and the <code>limit</code> sets the limit.
The sum of physpages.limit and swappages.limit limits the maximum amount
of allocated memory which can be used by a container. When physpages limit
is reached, memory pages belonging to the container are pushed out to
so called virtual swap (''vswap''). The difference between normal swap
and vswap is that with vswap no actual disk I/O usually occurs. Instead,
a container is artificially slowed down, to emulate the effect of the real
swapping. Actual swap out occurs only if there is a global memory shortage
on the system.
[[Category: UBC]]