[bbk5222] 第111集 第14章 数据库空间管理 00

以前市场上大都是512字节的磁盘，现在Oracle提供了4K扇区的磁盘，大大提高了I/O效率

通过可传输表空间，实现数据移植，平台间的移植;

通过可传输数据库，实现数据库整体移植.

Oracle可以不通过操作系统，直接操作物理磁盘，大大提高存储效率.

采用逻辑块访问，效率比访问直接物理地址要快.

数据库管理的核心，主要涉及到文件存储相关的管理配置.

SQL> select group#,blocksize from v$log;

    GROUP#  BLOCKSIZE
---------- ----------
         1        512
         2        512
         3        512

Objectives

After completing this lesson,you should be able to:

• Describe the concepts and use of 4KB-sector disks
• Use transportable tablespaces
• Describ the concepts of transportable databases

Database Storage

Supporting 4-KB Sector Disks

 

Using 4-KB Sector Disks

Emulation mode:

• Recommended 4-KB blokc size for logs
• Recommended 4-KB block size for(or large) for data files

Native mode:

• Mandatory 4-KB block size for logs
• Mandatory 4-KB block size(or large) for data files

Not affected:

• Control file block size :16KB

Specifying the Disk Sector Size

Using the SECTOR_SIZE and BLOCKSIZE clauses of the following commands

• CREATE DISKGROUP
• ALTER DATABASE
• CREATE DATABASE
• CREATE CONTROL FILE

Default sector size based on hardware(not the earlier 512-byte sectors)

CREATE DATABASE sample NORESETLOGS FORCE LOGGING

　　ARCHIVELOG

　　LOGFILE

　　　　GROUP 1 '$ORACLE_BASE/oradata/sample/redo01.log' SIZE 100M BLOCKSIZE 4096,
　　　　GROUP 2 '$ORACLE_BASE/oradata/sample/redo02.log' SIZE 100M BLOCKSIZE 4096
　　DATAFILE

　　...

1024*16*63*512=528M