ECS 3.6.2 Data Access Guide

Min/max governor for CAS bucket-level retention

From the ECS Portal, locate a CAS bucket and select Edit. All the features shown on the screen below are CAS-only features except for the Bucket Retention Period feature. Bucket Retention Period is the standard ECS bucket retention feature supported on all ECS bucket types.

Event-based retention

Event-based retention (EBR) is an instruction specifying that a record cannot be deleted before an event and during a specified period after the event. In CAS, EBR is a C-Clip with a specified base retention period or retention policy and an application-defined trigger that can set a longer retention period when the trigger fires. The retention period only begins when the trigger fires. When a C-Clip is marked for EBR, it cannot be deleted prior to the event unless a privileged delete is used.

When using EBR, the C-Clip life-cycle is as follows:

• Create: the application creates a new C-Clip and marks it as being under EBR. The application can provide a fixed retention period which acts as a minimum retention and it must provide an event based retention period or policy.
• Trigger Event: The application triggers the event, which is the starting point of the event-based retention period or retention policy. At this point the application can assign a new event-based retention period, provided that it is longer than the one assigned at the time of the C-Clip creation.
• Delete: When the application tries to delete the C-Clip, the following conditions must be met:
  • Policy (Namespace) retention has expired
  • Bucket retention has expired
  • Fixed retention has expired
  • The event has been triggered
  • Both the EBR set at the time of creation and any subsequent changes (extensions) at the time of the event have expired

The following figure shows the three possible scenarios for a C-Clip under EBR:

• C1 has a fixed or minimal retention which already expired before the event was triggered.
• C2 has a fixed or minimal retention which will expire before the EBR expires.
• C3 has a fixed or minimal retention which will expire after the EBR expires.

For non-compliant namespaces, privileged delete commands can override fixed and variable retention for EBR.

When applying EBR retention, it must comply with the Min/Max Governor settings for the variable retention period.

Litigation hold

Litigation hold allows CAS applications to temporarily prevent deletion of a C-Clip. Litigation hold is useful for data that is subject to an official investigation, subpoena, or inquiry and that may not be deleted until the investigation is over. Once there is no need to hold the data, the litigation hold can be released by the application and normal retention behavior resumes. The CAS application places and removes a litigation hold at the C-Clip level.

One C-Clip can be under several litigation holds. The application must generate unique litigation hold IDs and be able to track the specific litigation holds associated with a C-Clip. The application cannot query a C-Clip for this information. There is only a function that determines the litigation hold state of the C-Clip. If there is one or several litigation holds on the C-Clip, this function returns true, otherwise, it is false.

When using litigation hold, the C-Clip life-cycle is as follows:

• Create: The application creates a new C-Clip and provides a fixed and/or event-based retention period.
• Set litigation hold: An application puts the C-Clip on hold. This application can be different from the application that wrote the C-Clip.
• Release litigation hold: An application releases the C-Clip. This application can be different from the application that sets the litigation hold or wrote the C-Clip.
• Delete: When the application tries to delete the C-Clip, the following conditions must be satisfied:
  • There are no other litigation holds outstanding on the C-Clip.
  • Policy retention has expired.
  • Standard bucket retention has expired. (Standard bucket retention is available to all ECS object types, but is not recommended for CAS.)
  • Fixed retention period has expired (CAS-only feature).
  • Event-based retention has expired (CAS-only feature).

The following figure shows the three possible scenarios for a C-Clip put under litigation hold:

• C1 has a fixed retention that already expired when put under hold.
• C2 has a fixed retention that expires during the hold.
• C3 has a fixed retention that will expire after release of the hold.

A C-Clip can have multiple litigation holds assigned to it. If this is the case, each litigation hold requires a separate API call with a unique identifier for the litigation hold.