Home > Storage > ObjectScale and ECS > Product Documentation > Dell ECS with Commvault: Configuration and Best Practices > Auxiliary copy
The auxiliary copy operation creates additional standby copies of data. These standby copies are referred to as secondary copies. You can use different media and different libraries for the primary (for example, PowerScale) and secondary (ECS) copies.
An auxiliary (aux) copy writes a copy of an existing backup to a second location, which is usually a second storage library. Multiple copies of the same backup give the customer the flexibility of specifying different retention rates to preserve some copies for the long term and age out other copies in the short term. For example, the customer might keep short-term backups on PowerScale and long-term copies on ECS. An aux copy is run between two storage policies.
For detailed information about the auxiliary copy feature, see the following Commvault documentation: Additional Copies of Backup Data.
The procedures in this section assume that the ECS Cloud Library has already been created according to the guidelines in this document and the PowerScale Disk Library is available.
For information about PowerScale configuration and best practices to use with Commvault, see the Dell Isilon: Backup Using Commvault White Paper.
First, we create a secondary copy for long-term backups because we want to retain some backups for longer than the 15-day, 2-cycle retention that has been set on the primary Dell-OneFS copy:
You can specify a storage pool or library as the target for the new copy. We specified the cloud storage library, as shown in the following figure:
In this example, we set the retention to 360 days and 2 cycles to retain a copy for a longer period.
DASH is automatically enabled, which means that only unique data segments will be transferred to the target.
The secondary copy policy is then displayed along with the primary copy:
You can manually run an auxiliary copy to copy data from the primary to secondary storage policy, as follows: