New Memory on Demand setting for cloud servers in Selecto
News in one line: For MoD, a new parameter has appeared that allows you to more accurately control the behavior of the server when it is turned on. It is called start_memory .
When the cloud server has finished loading and the Memory on Demand technology is turned on, the memory is adjusted depending on the amount of used memory. However, this technology is tied to an agent working inside a virtual machine that sends information about the current memory usage of the mod server (outside the virtual machine). Thus, the system will be able to respond to a shortage of RAM only after launching the mod agent (it starts along with the rest of the services when the cloud server boots). In some cases, there is a need to immediately start from a “high start”, that is, from the very beginning to allocate a significant amount of memory.
By default, this value is set to the value of static_min, that is, to the minimum amount. Now this value can be changed explicitly.
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There are three strategies to use:
If MoD technology is disabled, this value allows you to manually change the current value of allocated memory (ranging from static_max to static_min) without rebooting, which can be useful in terms of technologies that do not like changing memory (Java, for example).
When the cloud server has finished loading and the Memory on Demand technology is turned on, the memory is adjusted depending on the amount of used memory. However, this technology is tied to an agent working inside a virtual machine that sends information about the current memory usage of the mod server (outside the virtual machine). Thus, the system will be able to respond to a shortage of RAM only after launching the mod agent (it starts along with the rest of the services when the cloud server boots). In some cases, there is a need to immediately start from a “high start”, that is, from the very beginning to allocate a significant amount of memory.
By default, this value is set to the value of static_min, that is, to the minimum amount. Now this value can be changed explicitly.
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There are three strategies to use:
- The server starts with the minimum value of memory, after which it begins to increase the amount of used memory as data loads or load increases. The default cloud servers behave this way (for which the MoD setting has not changed).
- The server is started with an overestimated value of memory, after which it is quickly “blown away” to the required server. This configuration protects against memory shortages when a large database is suddenly requested by a large DBMS memory or by a large application that requests memory in large chunks rather than gradually.
- The amount of starting memory is set to approximately the desired value - in this case, mod works in the fine-tuning mode, that is, increases / decreases as circumstances change.
If MoD technology is disabled, this value allows you to manually change the current value of allocated memory (ranging from static_max to static_min) without rebooting, which can be useful in terms of technologies that do not like changing memory (Java, for example).
Source: https://habr.com/ru/post/180331/
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