ORA-01034: ORACLE not available ORA-27101

The reason is that the database archive log may be inconsistent due to illegal shutdown.

 startup mount
ORACLE instance started.

Total System Global Area 3240239104 bytes
Fixed Size                  2217712 bytes
Variable Size            1778387216 bytes
Database Buffers         1442840576 bytes
Redo Buffers               16793600 bytes
Database mounted.
SQL> recover database until time '2016-05-24';
Media recovery complete.
SQL> alter database open resetlogs;

 

Database altered.