Snapshot Retention Policies
The CTERA Portal retains previous file versions for each user, by using snapshots. Snapshots are read-only copies of files as they were at a particular point in time.
The CTERA Portal creates snapshots automatically and retains them according to a configurable snapshot retention policy that is provisioned via subscription plans. So long as a snapshot is retained by CTERA Portal, the relevant version of the user data can be retrieved.
What Does a Snapshot Retention Policy Specify?
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 will be retained. If daily snapshots are set to 0, then the hourly snapshot will be 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 will be retained. If daily snapshots are set to 0, then the daily snapshot will be 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 default retention period for deleted files is 30 days.
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 recycle bin. It is then retained in the recycle bin for a period of time (in 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 from their Cloud Drive using a Recycle Bin feature in the end user portal interface.
At What Level Can a Snapshot Retention Policy Be Applied?
Snapshot retention policies can be applied at the following levels:
• At the virtual portal level
In this case, the snapshot retention policy will apply to all users in the virtual portal.
A snapshot retention policy can be applied to both team portals and reseller portals.
• At the user level
It is possible to configure snapshot retention policies for individual users in the virtual portal.
What Happens When Both Levels of Snapshot Retention Policy Are Applied?
When a snapshot retention policy is assigned to a portal, the policy will be globally enforced as a set of maximum values for all users in the portal. Individual users in that portal can be assigned user-level snapshot retention policies, so long as the values in the user-level policy do not exceed those of the portal-level policy.
For example, assume that a team portal called example is assigned a subscription plan called example-plan, which includes the following snapshot retention policy.
• Retain 7 daily snapshots
• Retain 4 weekly snapshots
• Retain 12 monthly snapshots
Users in the example portal cannot be assigned a snapshot retention policy that exceeds the values specified in example-plan.
Therefore, users in this portal cannot be assigned the following snapshot retention policy:
• Retain 10 daily snapshots
• Retain 15 weekly snapshots
• Retain 17 monthly snapshots
However, they can be assigned the following snapshot retention policy:
• Retain 6 daily snapshots
• Retain 2 weekly snapshots
• Retain 9 monthly snapshots
CTERA Portal Snapshot Retention for the Cloud Drive Service
Each user account that uses the Cloud Drive service is assigned a home folder in the CTERA Portal, upon creation of the user account. The home folder (Cloud Drive) serves as the block destination for CTERA Cloud Storage Gateway and CTERA Cloud 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.
CTERA Portal Snapshot Retention for the Cloud Backup Service
Each CTERA Cloud Storage Gateway and CTERA Cloud 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 Cloud Storage Gateway or Cloud Agent.
When a CTERA Cloud Storage Gateway or CTERA Cloud Agent initiates a Cloud Backup job, the CTERA Portal automatically creates a snapshot of the cloud storage gateway's or Cloud Agent's backup folder. The snapshot's timestamp is the time at which the Cloud Backup job was initiated by the client.
Snapshot Consolidation
The snapshot consolidator is a scheduled job that runs every hour. It is responsible for deleting all the snapshots that should not be retained, according to the retention policy.