1、问题
SQL> shutdown immediate
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux-x86_64 Error: 2: No such file or directory
SQL> startup;
ORA-27102: out of memory
Linux-x86_64 Error: 12: Cannot allocate memory
Additional information: 26
Additional information: 557060
Additional information: 1677721600
2、处理
获取pfile文件，利用pfile文件启动数据库
[oracle@localhost ~]$ find /u01/ -name 'pfile'
/u01/oracle/app/admin/icdc/pfile
-rw-r-----. 1 oracle oinstall 2058 12月 12 2018 init.ora.11122018161750
启动数据库
SQL> startup pfile='/u01/oracle/app/admin/icdc/pfile/init.ora.11122012161750'
ORACLE instance started.
Total System Global Area 534462464 bytes
Fixed Size 2254952 bytes
Variable Size 213911448 bytes
Database Buffers 310378496 bytes
Redo Buffers 7917568 bytes
Database mounted.
Database opened.
少一个步骤 通过pfile正常启动后你应该
create spfile from memory;
这样下次就可以正常启动了。