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I/O、內(nèi)存、網(wǎng)絡(luò)性能優(yōu)化命令 iostat , vmstat,netstat( 二 )

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0 0 0 11456 4120 1 41 19 1 3 0 2 0 4 0 0 48 112 130 4 14 82
0 0 1 10132 4280 0 4 44 0 0 0 0 0 23 0 0 211 230 144 3 35 62
0 0 1 10132 4616 0 0 20 0 0 0 0 0 19 0 0 150 172 146 3 33 64
0 0 1 10132 5292 0 0 9 0 0 0 0 0 21 0 0 165 105 130 1 21 78




The fields of vmstat"s display are
procs
r in run queue
b blocked for resources I/O, paging etc.
w swapped

memory (in Kbytes)
swap - amount of swap space currently available
free - size of the free list

page ( in units per second).
re page reclaims - see -S option for how this field is modified.
mf minor faults - see -S option for how this field is modified.
pi kilobytes paged in
po kilobytes paged out
fr kilobytes freed
de anticipated short-term memory shortfall (Kbytes)
sr pages scanned by clock algorithm

disk ( operations per second )
There are slots for up to four disks, labeled with a single letter and number.
The letter indicates the type of disk (s = SCSI, i = IPI, etc) . The number is
the logical unit number.

faults
in (non clock) device interrupts
sy system calls
cs CPU context switches

cpu - breakdown of percentage usage of CPU time. On multiprocessors this is an a
verage across all processors.
us user time
sy system time
id idle time

結(jié)果和解決方案:

A. CPU issues:

下面幾列需要被察看，以確定cpu是否有問題

Processes in the run queue (procs r)
User time (cpu us)
System time (cpu sy)
Idle time (cpu id)
procs cpu
r b w us sy id
0 0 0 4 14 82
0 0 1 3 35 62
0 0 1 3 33 64
0 0 1 1 21 78



問題情況:
1.) 如果processes in run queue (procs r)的數(shù)量遠(yuǎn)大于系統(tǒng)中cpu的數(shù)量，將會(huì)使系統(tǒng)便慢 。
2.) 如果這個(gè)數(shù)量是cpu的4倍的話，說明系統(tǒng)正面臨cpu能力短缺,這將使系統(tǒng)運(yùn)行速度大幅度降低
3.) 如果cpu的idle時(shí)間經(jīng)常為0的話，或者系統(tǒng)占用時(shí)間(cpu sy)是用戶占用時(shí)間(cpu us)兩輩的話，系統(tǒng)面臨缺少cpu資源

解決方案 :
解決這些情況，涉及到調(diào)整應(yīng)用程序，使其能更有效的使用cpu，同時(shí)增加cpu的能力或數(shù)量 。

B. Memory Issues:
內(nèi)存的瓶頸取決于scan rate (sr)。scan rate是每秒時(shí)鐘對(duì)頁(yè)的掃描 （he scan rate is the pages scanned by the clock algorithm per

second.）如果 scan rate (sr)一直大于200 pages每秒，這時(shí)就是內(nèi)存短缺的現(xiàn)實(shí) 。

解決方案 :
1. 調(diào)整應(yīng)用和服務(wù)器，使其能更好的使用memory和cache
2. 增加系統(tǒng)內(nèi)存
3. Implement priority paging in s in pre Solaris 8 versions by adding line "set priority paging=1" in
/etc/system. Remove this line if upgrading from Solaris 7 to 8 & retaining old /etc/system file.

Network Statistics (netstat)

netstat通過選項(xiàng)來顯示不通的網(wǎng)絡(luò)相關(guān)的數(shù)據(jù)結(jié)構(gòu)（netstat displays the contents of various network-related data structures

in depending on the options selected.）

語(yǔ)法 :

netstat

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