1、单节点启动时，是可以操作的
[oracle@rac1 ~]$ sqlplus / as sysdba
从事服务器托管机柜，服务器租用，云主机，虚拟主机，申请域名，CDN，网络代维等服务。
SQL*Plus: Release 11.2.0.3.0 Production on Thu Jul 11 11:54:29 2019
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
SQL> SELECT inst_name FROM v$active_instances;
INST_NAME
--------------------------------------------------------------------------------
rac1:RAC1
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
[oracle@rac1 ~]$ 2、新节点加入问题，正常运行后是否自动加入（是）
[oracle@rac1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.3.0 Production on Thu Jul 11 12:01:42 2019
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
SQL> SELECT inst_name FROM v$active_instances;
INST_NAME
--------------------------------------------------------------------------------
rac1:RAC1
rac2:RAC2
SQL> 3、默认rac是自动启动相关服务的
4、非图形化并没有节省多少资源