在红帽Linux系统装db2 v9.5，安装很顺利（装两次，一次用db2_install命令，一次用db2setup命令），但无论是图形安装时创建实例还是在字符界面安装好后创建实例，实例都无法启动，执行db2start命令没任何反应。最后在CU搜到一个帖子，执行命令：
export LANG=en.US 后解决问题

当时字符集设置为：LANG=zh_CN.GB18030

export LANG=zh_CN.GB18030
echo $LANG
zh_CN.GB18030

启动实例，没任何反应

把字符集改为en.US后启动正常：
echo $LANG
en.US
$ db2start
SQL1063N DB2START processing was successful

因为我没有设定LC_ALL或LC_*的值，所以执行export LANG=zh_CN.GB18030后，locale的结果LC_XX的值都是zh_CN.GB18030，如下：
$ locale
LANG=zh_CN.GB18030
LC_CTYPE="zh_CN.GB18030"
LC_NUMERIC="zh_CN.GB18030"
LC_TIME="zh_CN.GB18030"
LC_COLLATE="zh_CN.GB18030"
LC_MONETARY="zh_CN.GB18030"
LC_MESSAGES="zh_CN.GB18030"
LC_PAPER="zh_CN.GB18030"
LC_NAME="zh_CN.GB18030"
LC_ADDRESS="zh_CN.GB18030"
LC_TELEPHONE="zh_CN.GB18030"
LC_MEASUREMENT="zh_CN.GB18030"
LC_IDENTIFICATION="zh_CN.GB18030"
LC_ALL=
受http://publib.boulder.ibm.com/in ... c/doc/c0052657.html文章的启发，我进行了以下实验：
export LANG=zh_CN
export LANG=zh_CN.GB2312
export LANG=zh_CN.UTF-8
以上字符集设置以及前面的en_US均能正常启动实例，就设置为zh_CN.GB18030不能启动

APAR status
Closed as program error.

Error description

If a non-supported codeset is specified for the server
instance, for example (on a Linuxamd64 machine):
export LC_ALL=zh_CN.gb18030
db2start will fail.
Function sqlonlsmapcp will fail with a SQLO_BADCP error, which
is then mapped to SQLO_NLS_INIT_FAILED in sqloNLSOneTimeInit.
We end up aborting the operation well before we'd ever create
the data file in ~/sqllib/tmp.
Nothing is logged in db2diag.log or on the console about the
db2start failure. The trace shows that DB2 eventually aborts
with a -1042.
Based on the output of 'locale -a', the zh_CN.gb18030 locale
is valid on this system.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:                                              *
* ALL                                                          *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* If a non-supported codeset is specified for the server       *
*                                                              *
* instance, for example (on a Linuxamd64 machine):             *
*                                                              *
* export LC_ALL=zh_CN.gb18030                                  *
*                                                              *
* db2start will fail.                                          *
* Nothing is logged in db2diag.log or on the console about the *
*                                                              *
* db2start failure. The trace shows that DB2 eventually aborts *
*                                                              *
* with sqlcode -1042.                                          *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade server to V95 FP4 or higher.                         *
****************************************************************

db2在Linux下字符集问题