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If you want to represent many HW or SW H/W or S/W elements as resources, you need to define the order of operation for them.
For instance, the IP address does not mean anything without going through the physical network adapter phase.
Also, without running the DB engine service, you cannot run a DB connection client.The logical time order as discussed here is defined as a hierarchy relationship between a parent and a child in MCCS.The parent resource is above the child resource.
When you start a group in MCCS, it will start going online from the bottom to the top.
The parent resource can go online only after all the child resources go online. When you terminate a group, it will start going offline from the top to the bottom.

 

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  1. When you remove the dependency relationship, press 'Select' in the palette.
  2. Select a link to remove.
  3. The selected link will have big points at the both ends of resource to indicate the selection made.
  4. On the selected link, right click with your mouse button and select 'Dependency Removal' in the popup screen.

 

Dependency Attribute

You can review and edit a dependency attribute when you select a dependency among resources.
There are 'OnlineDependency' and 'OfflineDependency' in the dependency attribute.
This is applied when you bring online and take offline a resource within 'Restartlimit'. (For more details about Restartlimit, Please refer to "7. Resource" in this manual.)

AttributeDescriptionTypeDefaultEditNote
OnlineDependency

This indicates that the child is also brought online or not when a resource online is initiated.
Types are STRONG and WEAK.
Child is not brought online when a resource online is initiated, if this set as WEAK.

STRINGSTRONGO 

OfflineDependency

This indicates that the parent is also taken offline or not when a resource offline is initiated.
Types are STRONG and WEAK.
Parent is not taken offline when a resource offline is initiated, if this set as WEAK.

STRING

STRONG O

 

 

Basic Dependency Cases among resources

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Actions due to dependency

Online/Offline of the group is performed from bottom to top according to the dependency in case of online, and from top to bottom in case of offline.
Following are a few examples how MCCS manages the resources after dependency link among the resources when a resource is failed. 
Attributes and state of resources are defined as the figure below.

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[Figure] Resource State Information Charts

 

Action by dependency attribute

  • OnlineDependency

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[Figure] Example of bring online of resource r1(OnlineDependency attribute of D1 between r1 and r2 is STRONG, OnlineDependency attribute of D2 between r1 and r3 is WEAK.) 

  1. MCCS check the Online Dependency attribute linked to r1.
  2. Child resources, r4 -> r2 -> r1, are brought online in order to hierarchy when initiate resource online of r1 due to attribute of D1 is STRONG.
    (r3 isn't brought online due to attribute of D2 is WEAK.)


  • OfflineDependency

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[Figure] Example of take offline of resource r4.(D1의 OfflineDependency attribute of D1 between r2 and r4 is STRONG, OfflineDependency attribute of D2 between r3 and r4 is WEAK.) 

  1. MCCS checks OfflineDependency attribute linked to r4.
  2. Parents resources, r1 -> r2 -> r4, are taken offline in order to hierarchy when initiate resource offline of r4 due to attribute of D1 is D1 STRONG.
    (r3 isn't taken offline due to attribute of D2 is WEAK.)


Resource Critical Attributes

  • Failure occurs from a resource on which critical resource depend.

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RestartLimit is an attribute of the resource type. This value determines how many times the recovery will be attempted until it is finally confirmed that it is failure. 
(Please refer to "67. Resource Type" for more details.)

 

[Figure] Example of Failure Occur 3

  1. On the assumption that the value of RestartLimit is 1 for resource r2, the first failure has occurred.
  2. MCCS will bring online resource r2 again as the value of RestartLimit. 
    At this time, resource r1 which depends on resource r2 will be taken offline.
  3. resource r2 restart.
  4. resource r1 online.
  5. When another failure occurs on resource r2, all of the resource will be taken offline from resource r1 to r3 by order.
  6. Resource r3 will be taken offline.
  7. As a result, resource r2 is considered as failure and all resources in the group is offline status in the node.


※ When it restart bring online of a group in a node due to failure, parent resources are taken offline first based on OfflineDependency attribute in the failure node. And then, bring online resources through the hierarchy..