swap使用率持续升高是什么原因？

Niy38

最初由 hulu 发布
[B]哦，知道了，刚才上网查了一下：如果物理内存<2G，则swap=物理内存×2；如果物理内存在2G-8G，则swap=物理内存；如果物理内存>8G，则swap=物理内存/2；

.... [/B]

forget this rule.

for some old unix version, like SunOS,
   virtual memory space=swap
so swap MUST be biggerr than ram, to
hold every processes in swap, only working
set of process stay in the ram. then 2x rule
appeared.

But for most unix now, including linux, swap
is just extension of ram:
    virtual memory space=ram+swap
So depend on your system load, you can
allocate swap space according to you
need.

For Oracle server, it need to keep
SGA and PGA in ram ( otherwise decrease
the size of SGA and PGA), so it doesn't matter
what's the size of swap. But if the system also
running other process, then you have to setup some swap space.