Oracle trace日志报错:Warning: lio_listio returned EAGAIN

Oracle Trace日志报错，如下：

Warning: lio_listio returned EAGAIN
Performance degradation may be seen.
Warning: lio_listio returned EAGAIN
Performance degradation may be seen.
Warning: lio_listio returned EAGAIN
Performance degradation may be seen.
Warning: lio_listio returned EAGAIN

 

平台：AIX 5300-08-03-0831

数据库：Version 11.1.0.6.0

使用了aio：处理异步IO请求的核心进程.

以前没有出现过，只是最近增加了HDS存储，10块lun导致，google，发现高人指点出的aio参数问题

 

IBMg

 If the maxreqs value is too low, then the following Oracle warning message might be returned: Warning: lio_listio returned EAGAIN. This warning message indicates a need to increase the maxreqs value. When performing file system I/O, a maxservers value that is too low can also indirectly cause this warning message

 

修改参数：maxservers=(10 * number of logical disks / number of processors)

 

可能需要修改aio参数，察看现在的aio配置：

lsattr -El aio0

autoconfig available STATE to be configured at system restart True
fastpath   enable    State of fast path                       True
kprocprio  39        Server PRIORITY                          True
maxreqs    8192      Maximum number of REQUESTS               True
maxservers 20        MAXIMUM number of servers per cpu        True
minservers 1         MINIMUM number of servers                True

 

加上HDS存储后，lun的个数是25，cpu 8颗

lsdev -Cc processor
proc0  Available 00-00 Processor
proc2  Available 00-02 Processor
proc4  Available 00-04 Processor
proc6  Available 00-06 Processor
proc8  Available 00-08 Processor
proc10 Available 00-10 Processor
proc12 Available 00-12 Processor
proc14 Available 00-14 Processor

 

所以修改aio0参数如下：

chdev -l aio0 -P -a maxservers=40