关于checkpoint内存占用率问题的说明

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关于checkpoint内存占用率问题的说明

      关于内存占用率过高的问题，通过厂家解释和我们实际检查，发现实际上这是一个普遍的一个现象，这和基于linux系统的工作机制有关系（CP的系统基于linux内核），实际上与任何用户的情况是差不多的，具体你们可以登录检查。以下是checkpoint厂家关于内存占用高的详细解释。然后我查看了其他一些用户的防火墙内存占用率，情况基本差不多，仅供参考。

The terms 'free memory' or 'available memory' can have a literal connotation based on the physical properties / usage of a system's memory, and can have a slightly different logical connotation.

The Linux kernel will frequently consume nearly as much RAM as is available on a system, and use it for various buffers and caching. A process may launch, and require some memory, then release the memory when it quits; however, the Linux kernel may leave the memory 'cached' and not report it as 'free'. When a new process starts up, the same thing happens, and it then seems that the memory is not being marked as 'free'; however, the OS is simply caching the memory...

If the same memory content is needed again, the kernel can provide its content 'instantly', or if some new process starts and needs free memory, if there is no memory available from the completely 'free' store of memory, the kernel will immediately provide the oldest non-used portion of the cached memory to the application.

Technically, the 'cached' memory is not 'free' -- it is being cached!; however, the OS kernel is only caching it for performance enhancement, and if it is not currently in use, it is provided to any requesting application in just the same manner as 'free' memory, that has never been allocated previously.

The memory used by the OS's buffer/cache mechanism is literally in use/not free, as the buffer/cache mechanism is 'using' the memory; however, the OS kernel treats this memory as available for any application that needs it, and thus from a logical point of view, this memory is free/available for use.

To see the available memory on Linux-based systems, from a command line, use the free command. The 'logical' connotation of free memory is the sum of the 'free' + 'buffers' + 'cached' on the first line of the output.
Example:
spirit:~ # free

          total          used      free        shared        buffers  cached

Mem:      1295840        1272788    23052      0              51200    996336

-/+ buffers/cache:  225252  1070588

Swap:      1028120  179912  848208

In the example above, the system is mostly idling, with only OS processes running ('cpstop'ed). The OS reports "1272788" of "1295840" used; however, we see that the 'free' + 'buffers' + 'cached' = "1070588", which is 'logically' free for applications to use, and will be handed out by the kernel appropriately.

所以关于CheckPoint内存占用率过高的问题，我想至此应该算尘埃落定了吧。。。。。。

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crossbeam 操作系统是linux的

3com 安全appliance就是 oem crossbeam
一个很标准的linux