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공유 디스크 DR 리소스는 공유 볼륨과 원격지 서버 사이의 데이터복제를 관리합니다.
 

공유 디스크 DR 리소스는 공유 볼륨을 관리하는 3개의 서버로 구성되어지며 MCCS는 공유 볼륨을 구성하는 서버에서 동작합니다.
즉, 원격지 서버에는 MCCS가 동작하지 않습니다. 원격지 서버의 동작에 대해서는 MCCS가 관여하지 않으므로 관리자에 의한 수동 조작이나 사전에 처리 조치의 등록이 필요합니다.

데이터의 복제는 소스 볼륨(Source Volume)을 가진 서버에서 타겟 볼륨(Target Volume)을 가진 서버로 네트워크를 통해 이루어집니다. 이 때 공유 볼륨에 접근 하지 못하는 다른 소스 서버는 공유볼륨을 "NONE" 역할로 인식합니다.
따라서, 타겟 볼륨과 "NONE" 볼륨은 읽기/쓰기가 모두 허용되지 않는 잠금 상태입니다The shared disk DR resource replicate a shared disk volume of a cluster to an offsite node of disaster recovery purpose.

The shared disk DR resource is composed of three nodes that manage the shared volume. MCCS is only operable at the server that composes the shared volume.
In other words, MCCS is not involved with operation of the offsite node, so, administrators need to perform manual operation or register necessary actions for processing in advance.

Data is replicated from the source-primary node to the offsite target node and the source-secondary node that cannot access the shared volume recognizes the shared volume as the one having the "NONE" role.
Thus, the offsite target node and the "NONE" node are locked and you cannot write or read to and from them. The goal is to prohibit the use of the corresponding disk volume of the node so that the data integrity can be guaranteed.


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[Figure] Mirror Ring Diagram

데이터 동기화

미러링 방식은 동기 모드와 비동기 모드로 나뉘어지며, 이는 저장 요청에 대한 응답이 언제 발생하는지에 따라 결정됩니다.

비동기(Async) 모드

미러 볼륨에 대한 쓰기 요청 응답은 소스 볼륨에 대한 저장이 완료되는 즉시 이루어집니다. 타깃 볼륨으로 데이터가 전송되고 저장되기를 기다리지 않기 때문에 응답이 빠른 반면에 장애가 발생할 경우에는 그 시점에 전송되지 못한 데이터만큼의 데이터 불일치가 발생할 수도 있습니다.

동기(Sync) 모드

디스크에 대해 쓰기 요청이 발생하면 데이터는 소스 볼륨에 쓰여지는 동시에 타깃 볼륨에도 쓰여집니다. 쓰기 요청에 대한 최종적인 성공 응답은 소스와 타깃에 대한 쓰기가 모두 성공한 후에 이루어집니다. 응답속도는 느리지만 소스와 타깃 간의 데이터는 언제나 동일합니다.

Add

Add the shared disk DR resource. 공유 디스크 DR 리소스를 추가 하기 위해서는, 사전에 데이터를 복제할 원격지 서버에 복제 툴을 설치해야 합니다Mirroring Configuration

Data Mirror Mode

Mirroring is classified into a sync mode and an async mode depending on the time of response to a request for saving.

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.

Add

Add the DR shared disk resource. Before you can add the shared disk DR resource, you must install a copy tool at the remote server that data will be copied to.

 

  1. Select the group -> Right click with the mouse -> Add the resource.   
    리소스 위자드에서 공유 디스크 DR을 선택하고 Next 버튼을 클릭합니다. 

    리소스 위자드의 공유 볼륨셋에서는 공유 디스크 DR을 구성할수 있는 드라이브 문자와 , 이미 구성된 드라이브 문자가 표시 됩니다. 원격 서버에서는 정보를 조회 할 수 없으므로, 사용자가 드라이브 문자 및 주소를 입력해야 합니다. 

    Warning공유 디스크 DR 로 사용될 드라이브 문자는 클러스터를 구성하는 양쪽 서버에서 같은 드라이브 문자로 되어있어야 합니다.   
  2. In resource wizard, select a shared disk DR and click the Next button. 

  3. The shared volume set of resource wizard will display the drive characters that can be used to compose the shared disk DR and the existing drive characters that are already configured.
    You cannot inquire about information at the remote server. So, you need to enter IP addresses on your own. 

    Warning

    The drive characters to be used as the shared disk DR should be same on the both servers that compose a cluster. Data will be copied to the target node from the source node. The remote server cannot be the source. 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.


    Image RemovedImage Added
        [Figure] Shared Disk DR Resource Added


  4. 추가 설정을 클릭하여 동기화 모드와 디스크 검사 옵션을 정의 합니다Click the 'Additional Setup' to define the synch mode and the disk test option.

    Info

    <Sync mode> Once  Once selected, the sync mode cannot be reversed. So, be careful.
    Sync mode : Response is slow but there is no data loss involved. Async  Async mode : Relatively faster than the sync mode but it can suffer from data loss.
    <Disk test option> Set  Set the disk test command option. For more details on the function, refer to MSDN.

     Image RemovedImage Added
     [Figure] Shared Disk DR Additional Setting    공유디스크 DR 리소스 추가 완료 버튼을 누르면 아래와 같은 경고창이 출력됩니다.
    선택한 서버가 소스서버가 맞는지 다시 한번 확인합니다.  
    잘못 설정했다면 '취소' 버튼을 누르고 다시 설정합니다.
    Image Removed
    [그림] 공유디스크 DR 리소스 추가 완료 버튼을 클릭 했을 때 출력되는 경고창 


  5. Press the Finish button after adding the shared disk DR resource, the following warning screen will be displayed.
    Check again if it is the correct source server selected.
    If not, then click on the 'Cancel' button and set it again. 

    Image Added
    [Figure] The warning screen displayed when you press the Finish button after adding the shared disk DR resource   
     

  6. Click the 'Finish' button to add the shared disk DR resource. You can immediately check the result in the management web console.

 

Delete

Select the resource -> Right click with the mouse -> Delete the resource.
The deleted resource will immediately disappear from the management web console.   

Status

The following table explains the status changing of the MCCS resource caused by a user's command and the status. 
The command assumes that it is generated by a user.

Shared disk DR agent: Manages the mirror disk. Copying program should be installed. 

Status

Agent's functions

Description

Note

Online

In this status, you can access the source volume and perform a writing test properly.

 

Offline

Regardless of the mirror role, the LOCKVOLUME command is used to lock the volume. If the mirror volume is not defined, the LOCKVOLUME command is ignored and regarded as a failure.

 

Monitoring모니터링 하기전에 먼저 리소스 상태 업데이트를 합니다. 디스크 쓰기 테스트를 통해 리소스 상태를 결정합니다

Before monitoring, update the status of resource first. Perform a disk write test to determine the status of resource.
If the writing test is successful, it is regarded as the online state. If the writing test failed on the disk, it is regarded as the offline state.

 

Offline

Except for the online and trouble states, it is always offline.

 

Online

Type of operation is determined by the role of the mirror volume at the start node.
<Source volume> 1. Allow them to You can unlock and write to the volume. 2.잠금 해제는 복제 프로그램의 'UNLOCKVOLUME'으로 이루어지며  더티비트가 있는지 확인을 합니다.
<타깃볼륨 또는 None 볼륨> 1.미러 역할이 타깃 또는 None 볼륨일 경우 SWITCHOVERVOLUME 명령을 실행합니다To unlock, you can use the 'UNLOCKVOLUME' menu in the copy program. Check whether there are dirty bits.
<Target or NONE volume> 1. If the mirror role is target or NONE volume, run the SWITCHOVERVOLUME command.

 

Monitoring

Refer to the description of monitoring as above.

 

Trouble


If a writing test failed online, or an attempt to go online is failed, the trouble state is displayed.
*Failover deactivation state When a mirror network communication failure, target node or target disk failure occurs, the mirror state is changed from 'MIRRORING' to other, such as 'MIRROR_PAUSED'. If the mirror status is not 'MIRRORING', a failover will take place and it can cause data losses or damages. To prevent this problem, an agent deactivates the failover mode if the mirror status is not "MIRRORING". If the failover mode is deactivated, no failover will take place even if manual failover or troubles occur. If mirror network communication failures are recovered, and communication resumes, it will automatically perform RESYNC. When the mirror status is changed to MIRRORING, the failover mode will be also automatically activated.

 

Online

Refer to the above online command.

 

Offline

Regardless of the mirror role, the LOCKVOLUME command is used to lock the volume. If the mirror volume is not defined, the LOCKVOLUME command is ignored and regarded as a failure.

 

 
 

Attribute

Show the unique attribute of the shared disk DR resource.

ArgList Factor

Description

Type

Default

Modification

Note

ChkDsk

When the volume is mounted, according to the 'Disk Test Options', disk is tested for errors. If it is set to true, and if dirty bits are set to the online volume, the ChkdskArg option will be used to run checkdisk. Before running checkdisk, the mirror copying will be automatically stopped and resynchronization will be performed after finished.

BOOLEAN

false

O

 

ChkdskArg

When the checkdisk (Chkdsk) option is set to true, the check disk command option is activated.

STRING

/F

O

 

DirtyBit

It means that dirty bits are set to the target mirror volume. In general, if you need to check the integrity of the target volume, the system will set this.

BOOLEAN

false

X

 

DriveLetter

The mirror volume is assigned to the drive character. It should be configured to obtain the same value at the source and the target systems.

STRING

 

X

 

DRState

The mirror status of the mirror volume. It is renewed from an event log.

STRING

 

X

 

DRType

Determine the mirror synchronization mode. Set it to A or S. ( A - async mode, S - sync mode) * If it is set to asynch mode, data loss can occur.

STRING

A

X

 

ResyncNeed

It represents the total sum of the blocks requiring re-synchronizing.

INTEGER

 

X

 

ResyncTotal

It is the total sum of the re-synchronizing blocks.

INTEGER

 

X

 

SharedSrcIp

It is the IP address used to manage the volume shared between two nodes.

STRING

 

X

 

SharedSrcRole

It represents the role of the shared volume for each node.

STRING

 

X

 

TargetDRIp

The IP address used to copy the volume.

IP ADDRESS

 

X

 

TargetDRLetter

It is the drive character for the DR target volume.

STRING

 

X

 

TargetDRRole

It represents the role of the shared volume for the target DR node.

STRING

 

X

 

TotalSpace

It represents the total size of the target mirror volume.

INTEGER

 

X

 

UsedSpace

It represents the available size of the target mirror volume.

INTEGER

 

X

 

속성 값은 해당 리소스를 등록할 때에 입력된 값이며, '리소스 고유 속성'에서 값을 변경하거나 확인 할 수 있습니다.
  
 Attribute value of ArgList arguments are the values that are added resources and the value can be changed or viewed through ’Specified Attribute’ list on the detailed information panel.