在Oracle21c之后，一些目录发生了变化，如监听配置文件、dbs目录。 示例如下：
Oracle21c安装之后，目录如下
#$ORACLE_BASE目录下
admin audit cfgtoollogs dbs diag homes oradata product
[oracle@oracle21 oracle]$ pwd
/u01/app/oracle
# 19c $ORACLE_BASE目录下。ASM
[oracle@rac19c oracle]$ ls
admin audit cfgtoollogs checkpoints diag product
#检查Oracle21c目录
[oracle@oracle21 oracle]$ orabasehome
/u01/app/oracle/homes/OraDB21Home1
[oracle@oracle21 oracle]$ orabaseconfig
/u01/app/oracle
[oracle@oracle21 oracle]$
#检查19c目录
[oracle@rac19c ~]$ orabasehome
/u02/app/oracle/product/19.0.0/db_1
[oracle@rac19c ~]$ orabaseconfig
/u02/app/oracle/product/19.0.0/db_1
[oracle@rac19c ~]$ orabase
/u02/app/oracle
[oracle@rac19c ~]$
#检查21c监听状态及文件位置,如下所示，已经在/homes/OraDB21Home1/network/admin/listener.ora目录下，配置tnsnames也需要在该目录下
[oracle@oracle21 oracle]$ lsnrctl stat
LSNRCTL for Linux: Version 21.0.0.0.0 - Production on 20-AUG-2021 13:52:09
Copyright (c) 1991, 2021, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=oracle21)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 21.0.0.0.0 - Production
Start Date 20-AUG-2021 13:33:24
Uptime 0 days 0 hr. 18 min. 45 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/app/oracle/homes/OraDB21Home1/network/admin/listener.ora
Listener Log File /u01/app/oracle/diag/tnslsnr/oracle21/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=oracle21)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
Services Summary...
Service "c8209f27c6b16005e053362ee80ae60e" has 1 instance(s).
Instance "mydb21", status READY, has 1 handler(s) for this service...
Service "c9e6ddb27463ad21e0531550a8c0a46d" has 1 instance(s).
Instance "mydb21", status READY, has 1 handler(s) for this service...
Service "mydb21" has 1 instance(s).
Instance "mydb21", status READY, has 1 handler(s) for this service...
Service "mydb21XDB" has 1 instance(s).
Instance "mydb21", status READY, has 1 handler(s) for this service...
Service "mypdb21" has 1 instance(s).
Instance "mydb21", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@oracle21 oracle]$
检查数据库中一些信息
--检查spfile文件,已不在原来的ORACLE_HOME目录下
SQL> show parameter spfile
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
spfile string /u01/app/oracle/dbs/spfilemydb21.ora
SQL>
虽然Oracle21c中想变化为只读目录，但目前查看目录权限，仍然可写。 权限如下：
SQL> Disconnected from Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
[oracle@oracle21 oracle]$ pwd
/u01/app/oracle
[oracle@oracle21 oracle]$ ls -lrt
total 32
drwxr-xr-x. 3 oracle oinstall 4096 Aug 19 16:18 product
drwxrwxr-x. 23 oracle oinstall 4096 Aug 19 16:35 diag
drwxr-x---. 3 oracle oinstall 4096 Aug 19 16:35 homes
drwxr-x---. 5 oracle oinstall 4096 Aug 19 16:42 cfgtoollogs
drwxr-x---. 3 oracle oinstall 4096 Aug 19 16:53 admin
drwxr-x---. 3 oracle oinstall 4096 Aug 19 16:53 oradata
drwxr-x---. 3 oracle oinstall 4096 Aug 19 16:55 audit
drwxr-x---. 2 oracle oinstall 4096 Aug 20 13:53 dbs
[oracle@oracle21 oracle]$
目前Oracle21c已经将一些目录分离出来，权限管理可以越来越细化，更好保障数据库的安全，后续继续测试。
目录变更可参考：