增量备份数据库报错

现在有这样一个问题：执行增量备份报错，报错信息如下：

[db2inst1@standby db2dump]$ db2 backup db testdb online incremental to /opt

SQL2426N  The database has not been configured to allow the incremental backup

operation. Reason code = "2".

[db2inst1@standby db2dump]$

相关设置如下：

[db2inst1@standby db2dump]$ db2 get db cfg for testdb |grep -i log

Log retain for recovery status                          = NO

User exit for logging status                            = YES

Catalog cache size (4KB)              (CATALOGCACHE_SZ) = 300

Log buffer size (4KB)                        (LOGBUFSZ) = 2149

Log file size (4KB)                         (LOGFILSIZ) = 1024

Number of primary log files                (LOGPRIMARY) = 6

Number of secondary log files               (LOGSECOND) = 12

Changed path to log files                  (NEWLOGPATH) =

Path to log files                                       = /home/db2inst1/testdb/redolog/NODE0000/LOGSTREAM0000/

Overflow log path                     (OVERFLOWLOGPATH) =

Mirror log path                         (MIRRORLOGPATH) =

First active log file                                   = S0000015.LOG

Block log on disk full                (BLK_LOG_DSK_FUL) = NO

Block non logged operations            (BLOCKNONLOGGED) = NO

Percent max primary log space by transaction  (MAX_LOG) = 0

Num. of active log files for 1 active UOW(NUM_LOG_SPAN) = 0

Percent log file reclaimed before soft chckpt (SOFTMAX) = 0

HADR log write synchronization mode     (HADR_SYNCMODE) = NEARSYNC

HADR spool log data limit (4KB)      (HADR_SPOOL_LIMIT) = AUTOMATIC(0)

HADR log replay delay (seconds)     (HADR_REPLAY_DELAY) = 0

First log archive method                 (LOGARCHMETH1) = DISK:/home/db2inst1/testdb/archivelog/

Archive compression for logarchmeth1    (LOGARCHCOMPR1) = OFF

Options for logarchmeth1                  (LOGARCHOPT1) =

Second log archive method                (LOGARCHMETH2) = OFF

Archive compression for logarchmeth2    (LOGARCHCOMPR2) = OFF

Options for logarchmeth2                  (LOGARCHOPT2) =

Failover log archive path                (FAILARCHPATH) =

Number of log archive retries on error   (NUMARCHRETRY) = 5

Log archive retry Delay (secs)         (ARCHRETRYDELAY) = 20

Log pages during index build            (LOGINDEXBUILD) = OFF

Log DDL Statements                      (LOG_DDL_STMTS) = NO

Log Application Information             (LOG_APPL_INFO) = NO

请各位帮忙，因为是刚接触到db2，还有许多没有明白的地方。