For Oracle database in remote multi instance linux environment, an error is reported when executing conn/as SYSDBA: ora-01031: insufficient privileges. The solution process is as follows:

Step 1: find the sqlnet.ora file. Add the following two

SQLNET.AUTHENTICATION_SERVICES=(ALL)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT, HOSTNAME)

Step 2: after saving, exit and execute lsnrctl reload

Step 3: the following errors occur after I finish executing:

TNS-12555: TNS:permission denied
 TNS-12560: TNS:protocol adapter error
  TNS-00525: Insufficient privilege for operation
   Linux Error: 1: Operation not permitted```

To solve this problem, execute: Chmod 777/var/TMP/.Oracle

Step 4: specify the connection instance. The orcl here should fill in your own instance name.

export ORACLE_SID=orcl

Step 5: when reconnecting, an error is reported connected to an idle instance.
. Note that this only means that the instance is not started, which is not a big problem. First query the status select status from V $instance

Step 6: start

startup

Since then.