결과적으로 별 차이가 없긴하죠.

하지만 Oracle 이 추천하는 방법은 srvctl 명령어 사용입니다. cluster 환경하에서 svrctl 명령어가 더 많은 상황을 가정하고 점검등등을 하기 때문이라는 것 같네요. 자세한 이유는 아래를 참조하세요

There are some differences between the use of SQLPLUS and SRVCTL utilities.
- Both should result in the instance startup, but Oracle always recommend the use of the SRVCTL due to the fact that the SRVCTL does more, i.e. SRVCTL will perform a dependency analysis and will inform about cluster related problem if they exist, in a better way than the SQLPLUS which may just say that the instance is not starting. The SRVCTL command will try to start dependent resources (like the  vip/ons/listeners) in case they are not running.
- The SRVCTL utility always do some kind of pre-start of the instances such as updating the
OCR information instead of waiting for the check script of the instance resource to detect this
instance startup and update the OCR.
- With SRVCTL, the root user OS setup is used since inherited from the crsd.bin that will start the instances as oracle user. With SQLPLUS, the oracle user OS setup is used. Having different user setups for root or oracle will make that the performance can be different (fragmented sga or not, another 'solaris' project setup, ...) Check Note 603051.1 , Note 369424.1 .

The common part however is that SRVCTL is using SQLPLUS to start/stop the instances.

The SRVCTL tool manages configuration information that is used by several other Oracle tools.
For example, Enterprise Manager uses the configuration information that SRVCTL generates to discover
and monitor nodes in your cluster.

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