Prevent archive changes

To protect a historical archive from being overwritten, we recommend using the EditDays tuning parameter to set a time limit for archive changes. Using the EditDays parameter, you specify a time limit in number of days prior to the current time in which events can be inserted or edited. The snapshot rejects events with time stamps earlier than the limit. By default there is no limit.

While it is possible to set an archive file to read-only, doing so can result in data loss due to the following reasons:

• Degraded Performance:

  • Read-Only Archives: When archives are set to read-only, incoming events must pass through the event queues and the archive subsystem's write cache before being discarded, which can degrade the archive subsystem's performance. This process can lead to data loss as the system struggles to handle the workload.

  • EditDays Parameter: With EditDays enabled, the snapshot subsystem discards events with timestamps earlier than the specified limit before they enter the event queues, preventing performance degradation and reducing the risk of data loss.

• Client Error Messaging:

  • Read-Only Archives: Clients attempting to write to read-only archives do not receive error messages, giving the false impression that their actions were successful. The errors are only logged on the Data Archive, potentially leading to unnoticed data loss.

  • EditDays Parameter: Clients receive immediate error messages when they try to write or edit data with older timestamps, ensuring they are aware of the issue and can take corrective action.

For more information, refer to the following resources:

• Degraded Archive Subsystem performance when trying to write data to read-only archives.

• How do I prevent editing historical archives?