oracle asm 磁碟管理什麼場景該用什麼樣的冗餘方式

    oracle asm 建立磁碟組的時候，有三種冗餘方式，

第一：外部冗餘方式，依賴於儲存的映象

第二：正常冗餘方式，asm儲存映象雙份映象方式

第三：高度冗餘方式，asm儲存映象三份映象方式

 

   Mirroring Options for ASM Disk Group Types
Disk Group Type       Supported Mirroring Levels     Default Mirroring Level
External redundancy     Unprotected (none)               Unprotected

Normal redundancy       Two-way
                                   Three-way
                                   Unprotected (None)              Two-way

High redundancy           Three-way                            Three-way

 

 

那什麼場景下該用哪種冗餘方式呢，以下是官方文件介紹

 

When Should External, Normal, or High Redundancy Be Used?
ASM mirroring runs on the database server and Oracle recommends to off load this
processing to the storage hardware RAID controller by using external redundancy. You
can use normal redundancy in the following scenarios:
■ Storage system does not have RAID controller
■ Mirroring across storage arrays
■ Extended cluster configurations
In general, ASM mirroring is the Oracle alternative to third party logical volume
managers. ASM mirroring eliminates the need to deploy additional layers of software
complexity in your Oracle database environment.

 

 

外部冗餘方式通常用於儲存上已經做好raid的映象方式

 

正常冗餘和高度冗餘用於儲存上沒有做raid映象方式，跨儲存陣列的映象，比如雙盤櫃，還有擴充套件叢集配置等。