崩溃恢复（crash recovery）与 AUTORESTART参数

       关于这个参数设置的影响，在生产系统中经历过两次：
       第一次是有套不太重要的系统安装在虚拟机，这套系统所有应用（DB2 WAS IHS）都配置到/etc/rc.local中，每次启动机器会自动拉起应用，然后有次虚拟机宕机，重启后检查了各个应用进程都正常启动，但是前台页面访问异常无法访问，然后到后台手动连接数据库报：
SQL1015N  The database is in an inconsistent state.  SQLSTATE=55025
根据SQL1015N提示：需要执行RESTART DATABASE DBNAME命令，执行后然后数据库可以正常连接

第二次是一套HA服务器的主机电源故障发生系统切换，切换到备机后，检查应用都正常被拉起，但是前台无法访问，和第一次是相同的问题，AUTORESTART参数被设置了OFF

这个参数解释如下：
       如果DB2数据库遭受断电或者异常关闭，数据库没有干净的关闭，那么数据库在启动的时候将会进行crash recovery. 但是如果数据库参数AUTORESTART设置为OFF的话，在启动数据库后DB2不会进行CRASH RECOVERY。关于crash recovery，在db2diag.log日志会有相关体现

下面重现这一场景：

/* 1
设置AUTORESTART为OFF
*/
[db2inst1@limt ~]$ db2 UPDATE DATABASE CONFIGURATION for limtdb USING AUTORESTART OFF IMMEDIATE
DB20000I
The UPDATE DATABASE CONFIGURATION command completed successfully.
[db2inst1@limt ~]$ db2 get db cfg for limtdb|grep -i AUTORESTART
Auto restart enabled
(AUTORESTART) = OFF
[db2inst1@limt yunwei]$ db2 connect to limtdb
Database Connection Information
Database server
= DB2/LINUXX8664 10.1.0
SQL authorization ID
= DB2INST1
Local database alias
= LIMTDB
/* 2
插入一条数据但不提交，为了数据库处于不一致性
*/
[db2inst1@limt yunwei]$ db2
+c "insert into A values(15485,'asdas','asdas')"
DB20000I
The SQL command completed successfully.
[db2inst1@limt yunwei]$
/* 3
kill数据库，模拟异常宕机情况
*/
[db2inst1@limt yunwei]$ ps -ef|grep db2sys
db2inst1
5287
5285
1 08:07 pts/1
00:00:04 db2sysc 0
db2inst1
5827
3612
0 08:12 pts/1
00:00:00 grep db2sys
[db2inst1@limt yunwei]$ kill -9 5287
/* 4
启动数据库，此时数据库没有进行崩溃恢复，因为AUTORESTART为OFF
*/
[db2inst1@limt yunwei]$
[db2inst1@limt yunwei]$ db2start
12/19/2014 08:13:04
0
0
SQL1063N
DB2START processing was successful.
SQL1063N
DB2START processing was successful.
[db2inst1@limt yunwei]$
[db2inst1@limt yunwei]$
/* 5
此处报错是因为刚才的db2bp进程没有terminate
*/
[db2inst1@limt yunwei]$ db2 connect to limtdb
SQL0752N
Connecting to a database is not permitted within a logical unit of
work when the CONNECT type 1 setting is in use.
SQLSTATE=0A001
[db2inst1@limt yunwei]$ db2 terminate
DB20000I
The TERMINATE command completed successfully.
/* 6
再次启动时候报数据库不一致 */
[db2inst1@limt yunwei]$ db2 connect to limtdb
SQL1015N
The database is in an inconsistent state.
SQLSTATE=55025
/* 7
db2 ? SQL1015N 有一条建议： using the RESTART DATABASE command*/
[db2inst1@limt yunwei]$ db2 restart database limtdb
DB20000I
The RESTART DATABASE command completed successfully.
/* 8
数据库可以正常连接*/
[db2inst1@limt yunwei]$ db2 connect to limtdb
Database Connection Information
Database server
= DB2/LINUXX8664 10.1.0
SQL authorization ID
= DB2INST1
Local database alias
= LIMTDB
/* 9
以下是设置AUTORESTART为ON情况下，数据库宕机重启(不需要执行RESTART DATABASE) */
[db2inst1@limt yunwei]$
[db2inst1@limt yunwei]$ db2 UPDATE DATABASE CONFIGURATION for limtdb USING AUTORESTART ON IMMEDIATE
DB20000I
The UPDATE DATABASE CONFIGURATION command completed successfully.
[db2inst1@limt yunwei]$
[db2inst1@limt yunwei]$ db2 get db cfg for limtdb|grep -i AUTORESTART
Auto restart enabled
(AUTORESTART) = ON
[db2inst1@limt yunwei]$
[db2inst1@limt yunwei]$
[db2inst1@limt yunwei]$ db2
+c "insert into A values(15485,'asdas','asdas')"
DB20000I
The SQL command completed successfully.
[db2inst1@limt yunwei]$ ps -ef|grep db2sys
db2inst1
5870
5868
1 08:13 pts/1
00:00:03 db2sysc 0
db2inst1
6122
3612
0 08:16 pts/1
00:00:00 grep db2sys
[db2inst1@limt yunwei]$ kill -9 5870
[db2inst1@limt yunwei]$ db2start
12/19/2014 08:16:35
0
0
SQL1063N
DB2START processing was successful.
SQL1063N
DB2START processing was successful.
[db2inst1@limt yunwei]$ db2 connect to limtdb
SQL0752N
Connecting to a database is not permitted within a logical unit of
work when the CONNECT type 1 setting is in use.
[db2inst1@limt yunwei]$ db2 terminate
DB20000I
The TERMINATE command completed successfully.
[db2inst1@limt yunwei]$ db2 connect to limtdb
Database Connection Information
Database server
= DB2/LINUXX8664 10.1.0
SQL authorization ID
= DB2INST1
Local database alias
= LIMTDB