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Add the mirror disk DR resource to a group.

Info

MCCS for linux Linux support DRBD which is open source for Mirror disk. Therefore, DRBD 8.3, 8.4 should be installed in advance.  

The size of disk file system that is created by mirror disk should be created with 128MB

128M space is required to store meta data that manages replication volume service.

Mirror Disk DR resource only support internal meta data type of mirror disk. For more detail about meta data type of mirror disk, please refer to '"7-6.7Mirror disk' Disk" of this guide.

Mirror IP address should be assigned a virtual IP address between active server and standby server in a primary site. So the virtual IP should be added in a group in advance.

Size of meta data can be changed according to the size of the meta data.

Please refer to DRBD meta data size. (Calculation for more details). ) 

When use both DBRB and LVM, only DRBD ON LVM is supported and LVM In DRBD is not supported. 

 

Warning

Mirror IP address of the cluster should be assigned a virtual IP address to represent each real IP addresses of both nodes in the primary site. So the virtual IP should be added in a group in advance.

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  1. Select a group → right click → '"Add Resource'".

  2. Select '"MirrorDisk'" from Resource Type lists and click 'Nextthe "Nex"' button.


  3. Select the mirror volume and MCCS will renewal the information automatically.

    The virtual device, mirror IP address and mirror ports will be entered automatically.

    Info

    If mirror volume is already configured in the volume, "mirrored" will be displayed.
    Also, the config data will be entered automatically during the selection, and you cannot change it. 


    [Figure] Mirror Disk DR Added



  4. Click the '"Finish' " button to add the mirror disk DR.

Deleting

Select resource "Resource type" → right click → delete resource.

  1. Click the "Delete resource" button and a confirming message about deleting resource will appear.

    [Figure] Check resource view

  2. Click the "OK" button and mirror disk is deleted.
    The deleted resource will immediately disappear from the management web console.

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StateAgent commandDescriptionNote

Online

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

Offline

If the role of mirror resource is online,Unmount (umount) the mirror disk from the mount point and the role of mirror disk demoted to secondary and offline the mirror disk resource.
If the mirror volume is not defined, the command is ignored and regarded as a failure.


Monitoring

MCCS consistently handles events of the replication component.
The MCCS event monitor is registered as an event receiver when starting the MCCS service. When a system event occurs, it will be automatically informed and it will detect the mirror disk status and role changes.
If the mirror disk's role is primary and it is mounted in the designated mount point, it is deemed to be online.
In other cases, it is recognized as an offline state.
In addition, when you register a new mirror disk, if it is in the primary condition where mounting is not yet to be done, the mirror disk's role is demoted to secondary.


Offline

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

Online

Type of operation is determined by the role of the mirror volume at the start node.
 
<Source volume>
After setting the role of mirror disk of the off-site DR node to Primary, mount it in the designated mount point. 

<Target volume>
If you want to go online at the node where the mirror role is target, the following conditions should be met.
1. Both nodes' mirror line conditions are connected.
2. Both nodes' disk status are UpToDate.
3. The other node's mirror disk role is secondary.

If the mirror disk is not defined, it is processed as a failure without any operation.


Monitoring

Refer to the description of monitoring as above.


Fault

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 has been failed and then, recovered as normal, mirror state is changed to RESYNC and data re-synching is initiated between primary cluster set and off-site DR node.

Online

Refer to the above online command.


Offline

If the role of mirror resource is online, Unmount (umount) the mirror disk from the mount point and the role of mirror disk is demoted to secondary.
If the mirror volume is not defined, the command is ignored and regarded as a failure.



*If the mirror volume is not defined, It is regarded as the offline state.

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Attribute

Description

TypeDefaultEditNote

ConnectState

Display the status of connection between the mirror volume's nodes.

STRING
X
DRConnectStateIt shows the connection state of mirror disk of off-site DR node.STRING
X
DiskStateDisplay the status of disk managed by the mirror volume.STRING
X
DRDiskStateIt shows the state of the mirror disk of off-site DR node.STRING
X
DRMirrorIPIt is an IP address of virtual device of MDR.STRING
X
DRMirrorPortIt is a port number of mirror disk.STRING
X
DRRoleStateIt shows the role of the mirror disk of off-site DR node.STRING
X
DRTargetIPIt is IP address of off-site DR node for the mirror disk.STRING
X
DRVritualDeviceIt is the virtual device name using mirror disk of offsite DR node.STRING
X
DRSyncedIt represents the progress of volume synchronization of off-site DR node.INTEGER0X
MDRVolumeNameIt shows the name granted to help DRBD managing the mirror disk.STRING
X
GIIt is an identifier used to determine whether each household's data copied by the mirror volume is of the latest version.STRING
X
GIStatusIt is the status value that compares each node's GI (Generation Identifier) values.STRING
X
KillBusyAppsWhen the mirror resource goes offline, determine whether to forcefully terminate the tasks that refer to the mirror resource.BOOLEANtrueO
LastMirrorOnlineTime

Record the system time where the mirror disk went online most recently.

System time is used for recording, it is not the absolute value that can determine whether the data is latest.
STRING
XLastPrimary

Display the role of the last DRBD volume before connected to the network.

True: The last role was primary.
False: The last role was secondary.

This value is valid only if a split brain occurs.

BOOLEAN

XMetaDiskIt is the disk where meta data is saved.STRING
X
MirrorIPIt an IP address used to mirror disk.STRING
X
MirrorNetConnectStatus

Display the connection status of the physical mirror network.

True: Mirror network connection.
False: Mirror network disconnection.

(Disconnection by a user's command does not affect the attribute.)

BOOLEANtrueX
MirrorPortIt is the communication port number used for mirror disk.STRING7789X

RoleState

Display the volume role managed by the mirror disk.

STRING
X

MountPoint

Display the mount point for the mirror volume managed by an agent.

STRING
X
MirrorVolumeIt is the name of block device  actually used by mirror disk.STRING
X
MountPointIt is the directory where the file system can be mounted. If there is no directory or if the directory is already in use, you cannot activate it.DIRECTORY
O
OOS

It is the OutOfSync value requiring synchronization.

If the value is non zero, it means that there is some data between the nodes not yet replicated or synchronized.
Thus, if the value is zero, a failover is prohibited. 

STRING0X
ProtocolTypeThis is a data transmission protocol type.
A = Async mode
B = Semi sync mode
C = Sync mode 		STRINGBX
ResyncRateThe ratio of resynchronization between the disk.INTEGER
X
RoleStateDisplay the role of the the mirror disk.STRING
X
SB0PolicyIf every member within a cluster is secondary, this split-brain recovery policy is automatically executed.STRING
X
SB1PolicyIf a member within a cluster is primary, this split-brain recovery policy is automatically executed.STRING
X
SB2PolicyIf every member within a cluster is secondary, this split-brain recovery policy is automatically executed.STRING
X

SplitBrainStatus

Display the split brain status.

True: Split brain occurred.
False: No split brain.

The attributes are valid only if the network disconnection status and GIStatus attributes have the following status values indicating that a split brain occurred.

SplitbrainDisconnect
SplitbrainTryAutoRecover

The value is set to false, when the split brain is resolved.

BOOLEANfalseX
SyncedIt represents the progress of volume synchronization.INTEGER0X
TotalSpaceIt represents the total size of the target mirror disk.INTEGER0X
UsedSpaceIt represents the available size of the target mirror disk.INTEGER0X
VirtualDeviceThis is a virtual device name used by mirror disk.STRING
X

 Specified attribute values are normally entered when add the resource, This value can be edited or viewed through 'Specified Attribute' table in the Resource Attributes tab on the detailed information panel.



Info

MCCS has function to limit input values against user's input field, and it provides function detects automatically data which is input wrong by user's mistake.