现象
　　[oracle@focorcl-ogg01 database]$ sqlplus / as sysdba
　　SQL*Plus: Release 11.2.0.4.0 Production on Thu Jul 7 23:51:15 2016
　　Copyright (c) 1982， 2013， Oracle.  All rights reserved.
　　Connected to an idle instance.
　　SQL> startup;
　　语句运行几分钟没有任何反应，alert_orcl.log中没有任何信息。
　　原因
　　*.log_archive_dest_1='location=/backup/redo/archive/'
　　*.log_archive_format='ARCH_%t_%s_%r.ARC'
　　*.memory_max_target=20480G
　　*.memory_target=20480G
　　[oracle@focorcl-ogg01 trace]$ cat /proc/meminfo
　　MemTotal:       49385184 kB
　　MemFree:        39167292 kB
　　系统内存为48G，结果oracle内存设置了20480G.
　　解决
　　[oracle@focorcl-ogg01 trace]$ sqlplus / as sysdba
　　SQL*Plus: Release 11.2.0.4.0 Production on Thu Jul 7 23:59:37 2016
　　Copyright (c) 1982， 2013， Oracle.  All rights reserved.
　　Connected to an idle instance.
　　SQL> create pfile='/u01/init.ora' from spfile;
　　File created.
　　[oracle@focorcl-ogg01 trace]$ vi /u01/init.ora
　　--修改
　　*.memory_max_target=20G
　　*.memory_target=20G
　　[oracle@focorcl-ogg01 trace]$ sqlplus / as sysdba
　　SQL*Plus: Release 11.2.0.4.0 Production on Fri Jul 8 00:01:29 2016
　　Copyright (c) 1982， 2013， Oracle.  All rights reserved.
　　Connected to an idle instance.
　　SQL> create spfile from pfile='/u01/init.ora';
　　File created.
　　SQL> startup;
　　ORACLE instance started.
　　Total System Global Area 2.1379E+10 bytes
　　Fixed Size          2262656 bytes
　　Variable Size        1.2885E+10 bytes
　　Database Buffers     8455716864 bytes
　　Redo Buffers           36073472 bytes
　　Database mounted.
　　Database opened.
　　问题解决。