大虾们，看看这个memory的问题吧

cuxxx

书上说，当内存不够用时，如果内存的空闲值低于物理内存的1/64时就开始往交换空间pageout了，我遇到了一个问题，当内存的空闲量为20是，交换分区的空闲量为70%， 当内存的空闲量为1%时，交换分区的空闲量居然不降反升为98%，且扫描速度（sr）和po值也为0，没有搞明白，那位高人能讲讲交换分区和内存的关系，授业解惑一下，谢谢！
再问一下，是不是内存用于data buffer的部分统计不出来？

[ 本帖最后由 cuxxx 于 2006-1-23 20:28 编辑 ]

cuxxx

期待高手指点。。。。。。
我略看了一下《The Solaris Memory System》，里面有这么一说：
*******************************************************
Sizing the buffer cache is somewhat more difficult. There is no fixed size of memory required for a buffer, it’s really sized by the payback between cost of additional memory and the performance gained by having a larger buffer.
A general rule of thumb is to use about 2% of the size of the dataset. For example, a 10GB database should have about 200MB of buffer cache.
If the database is on RAW filesystems, then buffer cache is not required for this, however the same amount of memory should be allocated for the shared memory buffer used by the database. If your database is on RAW, then you should still plan to leave about 10% of the total memory free for UFS buffer cache, which will be used by system processes, logfiles, and any other components that are on filesystems.

谁能解释一下RAW filesystems与RAW的区别，谢谢

[ 本帖最后由 cuxxx 于 2006-1-23 18:00 编辑 ]

Cygnus

原帖由 cuxxx 于 2006-1-23 17:58 发表
.. 谁能解释一下RAW filesystems与RAW的区别 ...

It's same thing here.

RAW = RAW filesystems = filesystems using RAW devices for databases

Cygnus

原帖由 cuxxx 于 2006-1-23 16:23 发表
书上说，当内存不够用时，如果内存的空闲值低于物理内存的1/64时就开始往交换空间pageout了，我遇到了一个问题，当内存的空闲量为20是，交换分区的空闲量为70%， 当内存的空闲量为1%时，交换分区的空闲量居然不降 ...

1. It seems you don't know how to monitor free memory. The real free memory is not the
    value of "free" in vmstat.


2. sr in vmstat is quite different between Solaris 8,9  and 7,6.


Please read << Solaris Internals >>

cuxxx

原帖由 Cygnus 于 2006-1-24 00:08 发表


1. It seems you don't know how to monitor free memory. The real free memory is not the
    value of "free" in vmstat.


2. sr in vmstat is quite different between Solaris 8,9  an ...

Thanks for your help, Cygnus!