Administrator Guide

1. Click Volumes.
2. Expand Volumes and then select the volume name.
3. In the Snapshots section of the Activities panel, click Modify snapshot policy.
4. In the dialog box, select either Set volume oine or Delete oldest snapshot.
NOTE: Snapshot space borrowing cannot be enabled if the Set volume oine option is selected. The Delete oldest
snapshot option enables snapshot space borrowing.
NOTE: You cannot select Set volume oine for recovery volumes.
5. To enable snapshot space borrowing, select Borrow snapshot space as needed.
To disable snapshot space borrowing, clear the checkbox.
NOTE: You can also control snapshot space borrowing under the Group Conguration Defaults tab. Settings
specied here apply to newly created volumes only, not to existing volumes.
About Replication
The replication technology provided by PS Series rmware enables you to copy volume data from one group to another, protecting
the data from a variety of failures, ranging from the destruction of a volume to a complete site disaster, with no eect on data
availability or performance.
Volume replication between dierent groups provides protection against data loss. If a volume is destroyed, you can fail over to the
recovery group and recover data from a replica. Users can then resume access to the recovery volume. After the original volume
becomes available, you can fail back to the original group.
Traditional replication is dierent from synchronous replication (SyncRep). You cannot enable synchronous replication on a volume for
which traditional replication is congured, and you cannot enable traditional replication on a volume for which synchronous replication
is congured.
NOTE: A group can have multiple replication partners. However, you can replicate a volume to only one replication
partner at a time. Choose the replication conguration that is right for your environment.
You can use PS Series replication functionality alone or with Auto-Snapshot Manager (for Linux and Windows), Dell Virtual Storage
Manager for VMware (formerly ASM/VE), or Storage Replication Adapter for VMware Site Recovery Manager. See the related
product documentation for details.
The rst step in implementing replication is to congure the replication partners. Replication partners can consist of two or more
groups. In the simplest case, a primary group contains the volume you want to replicate and a secondary group stores the replicated
data. Each partner plays a role in the replication of a volume, and you can monitor replication activity from either partner:
• Primary group
Location of the volume — The primary group administrator congures the secondary group as a replication partner and initiates
the volume replication operation. Replication of the volume is considered outbound from the view of the primary group.
• Secondary group
Location of the volume’s replica set — The secondary group administrator congures the primary group as a replication partner
and delegates space for storing replicas from the primary group. Replication of a volume is considered inbound from the view of
the secondary group (sometimes called the destination group).
Mutual authentication using passwords provides security between partners.
After you congure the two groups as replication partners, you can congure a volume or volume collection for replication, specifying
the replication partner, the local group space for the replication operation, and the remote partner space for storing the replicas.
The rst time you replicate a volume, the primary group copies the entire contents of the volume to the secondary group. For
subsequent replication operations, the primary group copies only the data that changed since the previous replication operation
started.
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About Backing Up and Protecting Your Data