Introduction to several storage formats of Oracle10g Database

This article briefly introduces several storage formats of Oracle10g databases for oracle beginners. If you need to learn more, please take a look.

1. Operating System File.

This is the most common method and the most common form of non-commercial operation mode (such as the testing environment in the development or development phase. When you install Oracle, if you choose the operating system file storage format, the Oracle data will be stored in the operating system and stored as files. It's like we play some single-host games, and your archive is the file of the operating system. The advantage of storing data in the form of files is that the database is easy to move. For example, if you copy Oracle data files directly to a computer, you can quickly copy the same database system. When reading and writing files, the operating system usually provides a cache for reading and writing, to avoid too much hard disk read and write damage to the disk. Therefore, storing data in the form of operating system files is equivalent to obtaining the operating system cache function.

2. Raw Partition.

Raw partitions are used to write databases directly on disks without passing through the operating system layer. Oracle specifically reads and writes this partition. Without the operating system, the speed and performance of reading and writing are a general leap. In some database applications that frequently read and write Oracle data, using bare partitions to store data can even improve performance by more than 30%. Of course, if the data is stored in an operating system file, if RAID is used in Unix to frequently read/write files, it is also a means to improve performance.

3. Automatic Storage Management.

Automatic Storage Management, also known as ASM, is a new storage format provided after 10 Gb of Oracle. This storage format seems to be a compromise between the first two storage formats. It is neither a file system of the host operating system nor a raw partition that is directly read and written by Oracle. It can be viewed as an Oracle-specific file system. Data files, control files, and log files can be stored on ASM. in ASM, these files also exist, in this case, the file format is the Oracle ASM format. In Linux, similar to ASM is LVM (logical Volume management), which can also be seen as a new file system form.

4. Cluster System OCFS (RAC ).

What is the full name of RAC? Real Application Cluster is a database storage form that is shared in the Cluster environment. In our database, if it is a standalone database, when the data file disk cannot be accessed, the database will be suspended. If a cluster shares a database, one of the methods is to store data files on a node, and the rest of the databases are shared through NFS or Samba, although the data processing capability of the database has been greatly improved, if the storage node fails, the database will also go down. OCFS is a non-resumable storage mode. The overall impression is that each data server has its own file system, however, these file systems seem to be the same file system, because data updates or other operations are unified. Even if a computer crashes, the rest of the servers still run without database exceptions, and it is very easy to add a new server. It is particularly suitable for commercial 7x24 service forms.

The four data storage methods in Oracle10g have been introduced. The most common method is the first one, but there are many other three forms in the commercial environment. Especially in large-scale commercial applications that require high reliability, the fourth RAC form is widely used. Of course, here is a brief introduction to the concepts of several file systems. For more information, see the Oracle Technical Manual.