Versions Compared

Version Old Version 24 New Version 25
Changes made by

JuneL (Unlicensed)

JuneL (Unlicensed)

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.
Section
Column

If you want to represent many HW or SW 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.

 

Column
width350px
Panel

이 페이지의 주요 내용Table of Contents

Table of Contents
maxLevel4

...

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.


[Figure] Resource State Information Charts

Critical Attributes

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

[Figure] Example of Failure Occur 1

  1. As a failure is occurred at resource r2, resource r1 will be taken offline. (Since resource r1 depends on resource r2 which is failed, resource r1 may cannot be online properly.)
  2. Since resource r1 has critical attribute, resource r3 and r4 will be taken offline in order to failover the group.
  3. As a result, resource r2 is considered as failure and all resources in the group will be taken offline
  • Non-critical Resources

[Figure] Example of Failure Occur 2

  1. Resource r1 which is not critical is online status.
  2. When resource r2 get failed, resource r1 will be taken offline because it dependent on resource r2.
  3. As r1 resource is not critical, group failover will be not performed. Therefore, the group will be partial online status.

RestartLimit Attribute

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 "6. 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.

 

...