© 2013, CTERA Networks. All rights reserved
Understanding CTERA
Portal Snapshot Retention
Policies
CTERA Portal
Datacenter Edition
August 2013
Version 3.2
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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 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.
Tip
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.
Tip
A week is defined as starting on Monday and ending on Sunday.
Example 1:
Let's say 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.
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About CTERA Portal Snapshot
Retention Policies
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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:
Let's say 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:
Let's say 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:
Let's say 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.
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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.
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 reseller portals and team portals.
At the user level
It is possible to configure snapshot retention policies for individual users in the virtual portal.
Tip
Applying a retention policy at the user level in a reseller portal is supported from v3.2.
Applying a retention policy at the user level in a team portal is supported from v4.0.
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, let us assume that a team portal called "acme" is assigned a subscription plan called "acme-plan", which includes the following snapshot retention policy.
Retain 7 daily snapshots Retain 4 weekly snapshots Retain 12 monthly snapshots
Users in the "acme" portal cannot be assigned a snapshot retention policy that exceeds the values specified in "acme-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
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However, they can be assigned the following snapshot retention policy:
Retain 6 daily snapshots Retain 2 weekly snapshots Retain 9 monthly snapshots
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Snapshot retention policies are part of subscription plans. Therefore, in order to configure a snapshot retention policy, it is necessary to create or edit a subscription plan.
The snapshot retention policy settings are configured in the Plan Details Wizard's Snapshot Retention Policy dialog box.
For information on configuring a snapshot retention policy at the virtual portal level or the user level, refer to CTERA Portal Administrator Guide Datacenter Edition, "Adding and Editing Subscription Plans".
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Configuring a Snapshot Retention
Policy
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In order to apply a snapshot retention policy, it is necessary to assign the subscription plan that contains the snapshot retention policy to the desired virtual portal or user.
For information on assigning a subscription plan to a virtual portal, refer to CTERA Portal Administrator Guide Datacenter Edition, "Assigning Virtual Portals to Global Plans".
For information on assigning a subscription plan to a user, refer to CTERA Portal
Administrator Guide Datacenter Edition, "Assigning User Accounts to Subscription Plans".
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Applying a Snapshot Retention
Policy
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The CTERA Portal supports provisioning both the Cloud Backup service and the Cloud Drive service to users. However, CTERA Portal snapshot retention differs for each service.
How Does the CTERA Portal Retain Snapshots for Backup
Folders?
Each CTERA C Series appliance 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 appliance or Cloud Agent.
The snapshot retention policy for backup folders is applied as follows: When a CTERA
appliance or CTERA Cloud Agent initiates a Cloud Backup job, the CTERA Portal automatically creates a snapshot of the appliance'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.
How Does the CTERA Portal Retain Snapshots for Home
Folders?
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 appliance and CTERA Cloud Agent sync operations.
The snapshot retention policy for home folders is applied according to the following set of rules:
1 Snapshot Duration: 1 hour
2 Snapshot Timestamp: Snapshot open time
3 If there were no changes in the home folder, a snapshot is not taken.
For example, consider the following scenario:
1 A file is synced to the cloud at 09:10 AM.
The CTERA Portal opens a snapshot for the user's home folder.
In accordance with rule 1, the snapshot is set to close at 10:10 AM.
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CTERA Portal Snapshot Retention
for Different Services
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2 A new file is synced to the cloud at 10:24 AM.
The CTERA Portal opens a new snapshot for the user's home folder.
In accordance with rule 1, the snapshot is set to close at 11:24 AM.
In accordance with rule 2, the old snapshot is registered in "Previous Versions" with a timestamp of 09:10 AM.
How Does CTERA Portal Retain Snapshots for Project
Folders?
Project folders snapshots are retained in the same way as Home Folder snapshots.
However, what happens when two collaborators (portal users) who are working on the same project have different snapshot retention policies? The project snapshots will be retained according to the project owner's retention policy.
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The snapshot consolidator is a scheduled job that runs once a day at midnight. It is responsible for deleting all the snapshots that should not be retained, according to the retention policy.
