oracle 版本是11203，linux 64位 服务器有做raid5
redo日志切换频率为大概半小时一次， redo文件的大小为950M
我觉得半小时切换一次日志好像并不频繁啊， 为什么还是老报 Thread 1 cannot allocate new log 的错误。
alert 日志文件如下
Thread 1 cannot allocate new log, sequence 25459
Private strand flush not complete
Current log# 7 seq# 25458 mem# 0: /oracle/oradata/sd/redo07.log
Thread 1 advanced to log sequence 25459 (LGWR switch)
Current log# 3 seq# 25459 mem# 0: /oracle/oradata/sd/redo03.log
Thu Jul 10 17:29:05 2014
ALTER SYSTEM SET sga_target='12G' SCOPE=SPFILE;
Thu Jul 10 17:50:37 2014
Thread 1 cannot allocate new log, sequence 25460
Private strand flush not complete
Current log# 3 seq# 25459 mem# 0: /oracle/oradata/sd/redo03.log
Thread 1 advanced to log sequence 25460 (LGWR switch)
Current log# 4 seq# 25460 mem# 0: /oracle/oradata/sd/redo04.log
Thu Jul 10 18:25:35 2014
Thread 1 cannot allocate new log, sequence 25461
Private strand flush not complete
Current log# 4 seq# 25460 mem# 0: /oracle/oradata/sd/redo04.log
Thread 1 advanced to log sequence 25461 (LGWR switch)
Current log# 5 seq# 25461 mem# 0: /oracle/oradata/sd/redo05.log
Thu Jul 10 19:00:36 2014
Thread 1 cannot allocate new log, sequence 25462
Private strand flush not complete
Current log# 5 seq# 25461 mem# 0: /oracle/oradata/sd/redo05.log
Thread 1 advanced to log sequence 25462 (LGWR switch)
Current log# 6 seq# 25462 mem# 0: /oracle/oradata/sd/redo06.log
Thu Jul 10 19:35:37 2014
Thread 1 cannot allocate new log, sequence 25463
Private strand flush not complete
Current log# 6 seq# 25462 mem# 0: /oracle/oradata/sd/redo06.log
Thread 1 advanced to log sequence 25463 (LGWR switch)
Current log# 8 seq# 25463 mem# 0: /oracle/oradata/sd/redo08.log
Thu Jul 10 19:56:38 2014
Thread 1 advanced to log sequence 25464 (LGWR switch)
Current log# 9 seq# 25464 mem# 0: /oracle/oradata/sd/redo09.log
Thu Jul 10 20:11:41 2014
***********************************************************************
Fatal NI connect error 12170.
VERSION INFORMATION:
TNS for Linux: Version 11.2.0.3.0 - Production
Oracle Bequeath NT Protocol Adapter for Linux: Version 11.2.0.3.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 11.2.0.3.0 - Production
Time: 10-7鏈?-2014 20:11:41
Tracing not turned on.
Tns error struct:
ns main err code: 12535
TNS-12535: TNS: 鎿嶄綔瓒呮椂
ns secondary err code: 12560
nt main err code: 505
TNS-00505: 鎿嶄綔瓒呮椂
nt secondary err code: 110
nt OS err code: 0
Client address: (ADDRESS=(PROTOCOL=tcp)(HOST=10.142.168.9)(PORT=38430))
Thu Jul 10 20:30:36 2014
Thread 1 cannot allocate new log, sequence 25465
Private strand flush not complete
Current log# 9 seq# 25464 mem# 0: /oracle/oradata/sd/redo09.log
Thread 1 advanced to log sequence 25465 (LGWR switch)
Current log# 1 seq# 25465 mem# 0: /oracle/oradata/sd/redo01.log
Thu Jul 10 21:05:37 2014
Thread 1 cannot allocate new log, sequence 25466
Private strand flush not complete
Current log# 1 seq# 25465 mem# 0: /oracle/oradata/sd/redo01.log
Thread 1 advanced to log sequence 25466 (LGWR switch)
Current log# 2 seq# 25466 mem# 0: /oracle/oradata/sd/redo02.log
Thu Jul 10 21:29:59 2014
ALTER SYSTEM SET pga_aggregate_target='10G' SCOPE=BOTH;
Thu Jul 10 21:40:35 2014
Thread 1 advanced to log sequence 25467 (LGWR switch)
Current log# 7 seq# 25467 mem# 0: /oracle/oradata/sd/redo07.log