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When the Primary disks get full, the system goes on copying to the Secondary-labeled disks. Please, keep in mind that Primary and Secondary are just labels. You can name the disks asper your as per your wish when adding them to the system. This is done via the Add Disk button (adding) and from the Information Lifecycle Management section (where rules are defined) you setthe name set the name for the disk.
Proxy is choosen to archive Proxy files to a different disk.
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