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[Figure] Mirroring Configuration

Replication Mode

Replication option employs both asynchronous and synchronous mirroring schemes. Understanding the advantages and disadvantages between synchronous and asynchronous mirroring is essential to the correct operation of this.

Async Mode

With asynchronous mirroring, each write is captured and a copy of this is made. That copy is queued to be transmitted to the target system as soon as the network will allow it. Meanwhile, the original write request is committed to the underlying storage device and control is immediately returned to the application that initiated the write. At any given time, there may be write transactions waiting in the queue to be sent to the target machine.  But it is important to understand that these writes reach the target volume in time order, so the integrity of the data on the target volume is always a valid snapshot of the source volume at some point in time.  Should the source system fail, it is possible that the target system did not receive all of the writes that were queued up, but the data that has made it to the target volume is valid and usable.

Sync Mode

With synchronous mirroring, each write is captured and transmitted to the target system to be written on the target volume at the same time that the write is committed to the underlying storage device on the source system.  Once both the local and target writes are complete, the write request is acknowledged as complete and control is returned to the application that initiated the write.  With synchronous mirroring, each write is intercepted and transmitted to the target system to be written on the target volume at the same time that the write is committed to the underlying storage device on the source system.  Once both the local and target writes are complete, the write request is acknowledged as complete and control is returned to the application that initiated the write.  

Adding

Add the mirror disk DR resource to a group.

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1. When add a resource from a group name, select a group → right click → 'Add Resource'. Or select Edit(E) from the main menu bar → select 'Add Resource'. Or select 'Add Resource' icon from the tool bar.
    
2. Select 'MirrorDisk DR' from Resource Type lists and click 'Next' button. When add a resource from the mirror disk DR resource type name, this step will be skipped.
   
   

3. Select the mirror volume and MCCS will renew the information.

   If you skip enter resource name, this will given 'Mirror_value' which value is selected driver letter.(Ex: Mirror_G)

   Warning

   미러 디스크 DR로 사용될 드라이브 문자 는 양쪽 서버와 DR서버는 같은 드라이브 문자로 되어있어야 합니다. [Drive characters in the SAN environment (shared disk) are also displayed in the list. So, make sure you select the accurate drive characters.] Data will be copied to the target node and DR node from the source node. Be careful when you select the drive character where data exists. If you try to add the existing mirror volume, <mirrored> will be added to the volume letter.

       

   
   [Figure] Mirror Disk DR Resource Added
   

      

4. 미러주소와 DR 미러 주소를 선택합니다. 

   
   

5. <동기화 모드> 선택합니다.

   동기화 모드는 한 번 선택하면 변경할 수 없으므로 주의해서 선택해야 합니다.
   왼쪽 콤보 박스는 Cluster내에 미러 라인에 대한 동기화 모드이고, 오른쪽 콤보 박스는 DR 미러 라인에 대한 동기화 모드 입니다.

   Sync mode : Response is slow but there is no data loss involved.
   Async mode : Relatively faster than the synch mode but it can suffer from data loss.
   

   
   

6. As 'Additional Settings', Check Disk option is available.

   Info
   <Check Disk Option> Set the check disk command option. For more details on the function, refer to MSDN.

   
   [Figure] check disk option

    

7. When click OK button, following popup message appear.
   Confirm selected server as source.
   If you select wrong sever, clock cancel button.
    
   [Figure] Alert popup message after click OK button  
   
   
8. Click the 'Finish' button to add the mirror disk DR resource.
   You can immediately check the result in the management web console.

Deleting

Select resource type → right click → delete resource.

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1. Click "Delete resource" and a confirming message about deleting resource will appear.
   
   [Figure] check resource view    
   
   
2. Click "OK" and a confirming message about deleting redundancy program of mirror configuration will. 
   
   [Figure] Delete physical mirror disk view   
   
   
3. Click "OK" and redundancy program is deleted. Click "Cancle" and only mirror disk DR is deleted. 
   The deleted resource will immediately disappear from the management web console.

상태

다음 테이블은 DR 쪽 상태와는 상관없이 클러스터내의 미러 상태와 사용자 명령에 의해 발생되는 MCCS 리소스의 상태 변화에 대한 설명입니다.
The command assumes that it is generated by a user.

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Attribute

Show the unique attribute of resource.

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