The Snapshot Retention Policy
  • 31 Jul 2022
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The Snapshot Retention Policy

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The snapshot retention policy applies to both types of snapshots: Backups from an agent or CTERA Edge Filer and snapshots of the CTERA Portal Cloud Drive. A retention policy specifies the following:

  • The number of hours to retain all snapshots
    Every snapshot is retained for this amount of time. After this time has passed for any given snapshot, the snapshot may be retained or deleted depending on the other settings.
  • The number of hourly snapshots to retain
    For example, if hourly snapshots are set to 10, then the last 10 hourly snapshots are retained. If daily snapshots are set to 0, then the hourly snapshot are deleted when the next hour starts.
  • The number of daily snapshots to retain
    For example, if daily snapshots are set to 10, then the last 10 daily snapshots are retained. If daily snapshots are set to 0, then the daily snapshot are deleted when the next day starts.
    Note

    A day is defined as starting at 00:00:00 and ending at 23:59:59.

  • The number of weekly snapshots to retain
    A weekly snapshot is the latest snapshot taken during the week.
    Note

    A week is defined as starting on Monday and ending on Sunday.

    Example 1: Snapshots were successfully taken every day until the current day, which is Sunday. The weekly snapshot is the one taken on Sunday, as it is the latest snapshot taken this week.
    Example 2: Snapshots were successfully taken every day until the current day, except the Saturday and Sunday snapshots, which were not taken because the device was turned off. The weekly snapshot is the one taken on Friday, as it is the latest snapshot taken this week.
  • The number of monthly snapshots to retain
    A monthly snapshot is the latest snapshot taken during the month.
    Example 1: Snapshots were successfully taken every day until the current date, which is April 30th. The monthly snapshot is the one taken on the 30th, as it is the latest snapshot taken this month.
    Example 2: Snapshots were successfully taken every day until the current date, except snapshots for the 25th through the 30th, which were not taken because the device was turned off. The monthly snapshot is the one taken on the 24th, as it is the latest snapshot taken this month.
  • The number of quarterly snapshots to retain
    A quarterly snapshot is the latest snapshot taken during the quarter.
    Example 1: Snapshots were successfully taken every day until the current date, which is the March 31. The quarterly snapshot is the one taken on March 31st, as it is the latest snapshot taken this quarter.
    Example 2: Snapshots were successfully taken every day until the current date, except snapshots for March 25 through 31 were not taken because the device was turned off. The quarterly snapshot is the one taken on March 24th, as it is the latest snapshot taken this quarter.
  • The number of yearly snapshots to retain
    A yearly snapshot is the latest snapshot taken during the year.
    Example 1: Snapshots were successfully taken every day until the current date, which is the December 31st. The yearly snapshot is the one taken on the 31st, as it is the latest snapshot taken this year.
    Example 2: Snapshots were successfully taken every day until the current date, except snapshots for the 25nd through the 31st were not taken because the device was turned off. The yearly snapshot is the one taken on the 24th, as it is the latest snapshot taken this year.
  • The numbers of days to keep deleted files
    The retention period for deleted files. This retention period applies only to the current snapshot.
    When portal users delete a file or a folder, either via the Web interface or via the local synchronization folder, the deleted data is moved to a trashcan. It is then retained in the trashcan for a number of days, defined in the retention policy of the user's assigned subscription plan. As long as files are retained, users can recover their deleted data.
    The minimum value is 1 day.
Note

The snapshots retention policy does not apply to the current snapshot, which remains on the portal until it is replaced by a newer snapshot. The moment a snapshot is not current it follows the retention policy, based on the time the snapshot was taken.

Configuring a Snapshot Retention Policy

The snapshot retention policy is configured as part of the subscription plan described in [Managing Subscription Plans] and specifically in steps 6 and 7 of the procedure [To add or edit a subscription plan:], in the Snapshot Retention Policy window.

Applying a Snapshot Retention Policy

The snapshot retention policy defined in the subscription plan can be applied globally as the default plan to both team and reseller portals.

Snapshot Retention for the Cloud Drive Service

Each user account using the Cloud Drive service is assigned a home folder in the CTERA Portal, when the user account is created. This Cloud Drive home folder serves as the block destination for CTERA Edge Filer and CTERA Drive (Agent) sync operations. Snapshots of Cloud Drive folders are taken for each folder once every five minutes, if there were any changes in the folder during that five minutes.

For example, assume a file is synced to the portal at 09:10am. The portal opens a snapshot which will close after 5 minutes, at 09:15am. At 09:24am a new file is synced to the portal and a new snapshot is opened that will close at 09:29am. Between 09:15am and 09:24am no snapshot is open, since there are no changes between the user local files and the files synced to the portal. The snapshot that closed at 09:15am is registered as a previous version, with the opening time for the snapshot, 9:10am.

Snapshot Retention for the Cloud Backup Service

Each CTERA Edge Filer and CTERA Drive (Agent) that uses the Cloud Backup service is assigned a dedicated backup folder in the CTERA Portal, which serves as the block destination for the gateway or Agent.

When a CTERA Edge Filer or CTERA Drive (Agent) initiates a Cloud Backup job, the CTERA Portal automatically creates a snapshot of theedge filer's or Agent's backup folder. The snapshot's timestamp is the time at which the Cloud Backup job was initiated by the client.


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