System metadata collisions

Content Platform Tenant Management Help

Version
9.7.x
File Size
4269 KB
Audience
anonymous
Part Number
MK-95HCPH002-19

A system metadata collision occurs when these events occur in the order shown:

  1. Different changes are made to the system metadata for a given object on each of two systems in a replication topology.
  2. The changed system metadata on one of the systems is replicated to the other system.
For example, suppose a user on one system changes the shred setting for an object while a user on the other system changes the index setting for the same object. When the object on either system is replicated to the other system, a system metadata collision occurs.

If a collision occurs when changed system metadata for a given object is replicated from one system (system A) in a replication topology to another system (system B) in the topology:

  • For changed system metadata other than the retention setting and hold status:
    • If the last change made on system A is more recent than the last change made on system B, HCP changes the system metadata on system B to match the system metadata on system A.
    • If the last change on system B is more recent than the last change on system A, HCP does not change the system metadata on system B.
  • For a changed retention setting:
    • If the retention setting on system A specifies a longer retention period than does the retention setting on system B, HCP changes the retention setting on system B to match the retention setting on system A.
    • If the retention setting on system B specifies a longer retention period than does the retention setting on system A, HCP does not change the retention setting on system B.
  • For a changed hold status:
    • If the object is on hold on system A but not on system B, HCP places the object on hold on system B.
    • If the object is on hold on system B but not on system A, HCP leaves the object on hold on system B.
Here are some examples of how HCP handles collisions when changed system metadata for a given object is replicated from one system (system A) in a replication topology to another system (system B) in the topology.

Example 1

The object starts out on both system A and system B with these system metadata settings:

  • Shred: false
  • Index: false

The list below shows a sequence of events in which the system metadata for the object is changed and the changes are then replicated.

  1. On system A, a client changes the shred setting to true.
  2. On system B, a client changes the index setting to true.
  3. The changes on system A are replicated to system B. The resulting settings for the object on system B are:
    • Shred: false
    • Index: true

Example 2

The object starts out on both system A and system B with these system metadata settings:

  • Retention: Initial Unspecified
  • Shred: false
  • Index: false

The list below shows a sequence of events in which the system metadata for the object is changed and the changes are then replicated.

  1. On system A, a client changes the retention setting to Deletion Prohibited.
  2. On system B, a client changes the retention setting to Deletion Allowed.
  3. On system B, a client changes the index setting to true.
  4. On system A, a client changes the shred setting to true.
  5. The changes on system A are replicated to system B. The resulting settings for the object on system B are:
    • Retention: Deletion Prohibited
    • Shred: true
    • Index: false

Example 3

The object starts out on both system A and system B with these system metadata settings:

  • Retention: Initial Unspecified
  • Hold: true
  • Shred: false
  • Index: false

The list below shows a sequence of events in which the system metadata for the object is changed and the changes are then replicated.

  1. On system A, a client changes the retention setting to Deletion Allowed.
  2. On system B, a client changes the retention setting to Deletion Prohibited.
  3. On system B, a client changes the index setting to true.
  4. On system A, a client changes the shred setting to true.
  5. On system A, a client releases the object from hold.
  6. The changes on system A are replicated to system B. The resulting settings for the object on system B are:
    • Retention: Deletion Prohibited
    • Hold: true
    • Shred: true
    • Index: false
  7. The changes on system B are replicated to system A. The resulting settings for the object on system A are:
    • Retention: Deletion Prohibited
    • Hold: true
    • Shred: true
    • Index: false