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ORACLE I/O 性能分析浅析

ORACLE I/O性能分析步骤：
1，性能分析的几个原则：
   a, 检查消息的成功率。（成功率必须>99%，否则测试无意义）
   b, 监测日志，不应出现异常。
2，分析CPU负荷。（mpstat可看多CPU情况，top->1可查看cpu情况)
   命令：mpstat -P ALL 2 10
3，再查找哪个磁盘I/O吃紧 (iostat -x 1)
   命令：iostat -x 1
   注意：r/s+w/s，await, svctm, %util 四者之间的关系。（见后面描述）
4，然后查找 ORACLE 系统表 v$filestat 得知表空间的访问频率。
   命令：Select phyrds,phywrts,d.name from v$datafile d,v$filestat f where f.file#=d.file# order by d.name

============
下面是实验室的测试结果：
1，看下面输出，其中iowait非常高，说明 oracle 可能存在 I/O 瓶颈。
[oracle@BJ-WAP-SA-1 ~]$ mpstat -P ALL 2 100
Linux 2.6.9-78.ELsmp (BJ-WAP-SA-1)      06/25/2010
09:02:59 AM CPU   %user   %nice    %sys %iowait    %irq   %soft %steal   %idle    intr/s
09:03:01 AM all    1.25    0.00    0.94   13.56    0.00    0.00    0.00   84.25   5902.50
09:03:01 AM    0    0.00    0.00    0.50    0.50    0.00    0.00    0.00   99.00      0.00
09:03:01 AM    1    1.00    0.00    1.50    1.00    0.00    0.00    0.00   97.00      4.50
09:03:01 AM    2    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.50
09:03:01 AM    3    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:03:01 AM    4    8.50    0.00    4.00    5.00    0.00    0.00    0.00   82.00   5460.00
09:03:01 AM    5    0.50    0.00    1.50   98.00    0.00    0.00    0.00    0.50    428.00
09:03:01 AM    6    0.00    0.00    0.00    3.50    0.00    0.00    0.00   96.00      0.00
09:03:01 AM    7    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      9.00
09:03:01 AM CPU   %user   %nice    %sys %iowait    %irq   %soft %steal   %idle    intr/s
09:03:03 AM all    0.06    0.00    0.12   12.41    0.06    0.00    0.00   87.34   1333.50
09:03:03 AM    0    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:03:03 AM    1    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      4.50
09:03:03 AM    2    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.50
09:03:03 AM    3    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:03:03 AM    4    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00   1014.50
09:03:03 AM    5    0.00    0.00    0.50   99.50    0.00    0.00    0.00    0.00    305.00
09:03:03 AM    6    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      0.00
09:03:03 AM    7    0.00    0.00    0.00    0.00    0.00    0.00    0.00 100.00      9.00
2，看下面输出，可以得到如下结论：
   
   a, cciss/c0d0p3 的 %util 为90.40%，说明CPU时间均用于排队了。
   b, 继续分析：(w/s+r/s)*svctm 表明在1秒内总的服务时间，如果它略等于1秒，说明消息过来比较均速。否则，说明消息非常不均速。
   c, 看其 await = 排队时间+svctm，相差较大，说明排队时间较长。
iostat -x 1
avg-cpu: %user   %nice %system %iowait %steal   %idle
           0.75    0.00    0.25   12.50    0.00   86.75
Device:    rrqm/s wrqm/s   r/s   w/s rsec/s wsec/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await svctm %util
cciss/c0d0   0.00 194.06 0.00 182.18    0.00 3009.90     0.00 1504.95    16.52     1.25    6.89   5.41 98.61
cciss/c0d0p1
             0.00   0.00 0.00 0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
cciss/c0d0p2
             0.00 27.72 0.00 29.70    0.00 459.41     0.00   229.70    15.47     0.33   11.23 10.30 30.59
cciss/c0d0p3
             0.00 150.50 0.00 150.50    0.00 2407.92     0.00 1203.96    16.00     0.90    6.02   6.01 90.40
cciss/c0d0p5
             0.00 15.84 0.00 1.98    0.00 142.57     0.00    71.29    72.00     0.02    8.00   8.00   1.58
cciss/c0d0p6
             0.00   0.00 0.00 0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
cciss/c0d0p7
             0.00   0.00 0.00 0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
avg-cpu: %user   %nice %system %iowait %steal   %idle
           0.00    0.00    0.12   12.50    0.00   87.38
Device:    rrqm/s wrqm/s   r/s   w/s rsec/s wsec/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await svctm %util
cciss/c0d0   0.00 158.00 0.00 157.00    0.00 2528.00     0.00 1264.00    16.10     1.67   10.64   6.37 100.00
cciss/c0d0p1
             0.00   0.00 0.00 0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
cciss/c0d0p2
             0.00 41.00 0.00 44.00    0.00 688.00     0.00   344.00    15.64     0.57   12.77 12.73 56.00
cciss/c0d0p3
             0.00 117.00 0.00 113.00    0.00 1840.00     0.00   920.00    16.28     1.11    9.81   8.09 91.40
cciss/c0d0p5
             0.00   0.00 0.00 0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
cciss/c0d0p6
             0.00   0.00 0.00 0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
cciss/c0d0p7
             0.00   0.00 0.00 0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00

3， 看下面输出，在三个表空间 undotbs01.dbf，system01.dbf 和 wapgw_data_tablespace.dbf 访问非常频繁。尤以undotbs01.dbf为最繁忙。
SQL> select phyrds,phywrts,d.name from v$datafile d,v$filestat f where f.file#=d.file# order by d.name;
PHYRDS PHYWRTS NAME
------ ------- --------------------------------------------------------------------------------
37583   35088 /bases/oradata/wapgw_data_tablespace.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100624_21.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100624_22.dbf
    74      22 /opt/oracle/oradata/CMCCWAP/120100624_23.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_00.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_01.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_02.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_03.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_04.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_05.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_06.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_07.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_08.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_09.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_10.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_11.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/120100625_12.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_13.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_14.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_15.dbf
PHYRDS PHYWRTS NAME
------ ------- --------------------------------------------------------------------------------
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_16.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_17.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_18.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_19.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_20.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_21.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_22.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/120100625_23.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_04.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_05.dbf
    94      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_06.dbf
    94      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_07.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_08.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_09.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_10.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_11.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_12.dbf
   104      12 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_13.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_14.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_15.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_16.dbf
PHYRDS PHYWRTS NAME
------ ------- --------------------------------------------------------------------------------
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_17.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_18.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_19.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_20.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_21.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_22.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100624_23.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_00.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_01.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_02.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_03.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_04.dbf
    64      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_05.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_06.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_07.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_08.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_09.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/RADIUS120100625_10.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_04.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_05.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_06.dbf
PHYRDS PHYWRTS NAME
------ ------- --------------------------------------------------------------------------------
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_07.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_08.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_09.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_10.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_11.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_12.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_13.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_14.dbf
    34      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_15.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_16.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_17.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_18.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_19.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_20.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_21.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_22.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100624_23.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_00.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_01.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_02.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_03.dbf
PHYRDS PHYWRTS NAME
------ ------- --------------------------------------------------------------------------------
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_04.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_05.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_06.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_07.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_08.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_09.dbf
    84      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_10.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_11.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_12.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_13.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_14.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_15.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_16.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_17.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_18.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_19.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_20.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_21.dbf
   104      22 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_22.dbf
   104      12 /opt/oracle/oradata/CMCCWAP/SOCKET120100625_23.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/cmcc_user_data_tablespace_1.dbf
PHYRDS PHYWRTS NAME
------ ------- --------------------------------------------------------------------------------
    44      22 /opt/oracle/oradata/CMCCWAP/cmcc_user_data_tablespace_2.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/cmcc_user_data_tablespace_3.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/cmcc_user_data_tablespace_4.dbf
    44      22 /opt/oracle/oradata/CMCCWAP/cmcc_user_data_tablespace_5.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/cwmlite01.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/drsys01.dbf
   173      22 /opt/oracle/oradata/CMCCWAP/example01.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/indx01.dbf
    34      22 /opt/oracle/oradata/CMCCWAP/odm01.dbf
10566     451 /opt/oracle/oradata/CMCCWAP/system01.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/tools01.dbf
5152 115890 /opt/oracle/oradata/CMCCWAP/undotbs01.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/users01.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/wap_archiving_data_1.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/wap_archiving_data_2.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/wap_archiving_data_3.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/wap_archiving_data_4.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/wap_archiving_data_5.dbf
    32      22 /opt/oracle/oradata/CMCCWAP/wap_user_data_tablespace_1.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/wap_user_data_tablespace_2.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/wap_user_data_tablespace_3.dbf
PHYRDS PHYWRTS NAME
------ ------- --------------------------------------------------------------------------------
    35      35 /opt/oracle/oradata/CMCCWAP/wap_user_data_tablespace_4.dbf
    24      22 /opt/oracle/oradata/CMCCWAP/wap_user_data_tablespace_5.dbf
    28      22 /opt/oracle/oradata/CMCCWAP/xdb01.dbf