Volume Collections
Volume collections are sets of volumes that share data-protection characteristics, such as snapshot and replication schedules.
Snapshots for all volumes in a collection are captured synchronously to ensure that the data across these volumes is mutually consistent. Volumes in a collection share replication and snapshot schedules, as well as the retention policies for the snapshots. For disaster recovery, all volumes in a volume collection can simultaneously fail over to the replication partner.
Volume collections are limited to one downstream replication partner. If you need to replicate to multiple partners, create a separate volume collection for each replication partner you want to replicate to.
You can create a volume collection for each application. Volume collections can contain multiple schedules, which affect all volumes assigned to the collection. These schedules are additive, so when schedules overlap, snapshots and replicas are created for every schedule. Use synchronization when you create volume collection schedules that are specific to some Microsoft applications or VMware virtual machines to ensure consistency.
When configuring protection schedules, either as protection templates or as part of a volume collection directly, be sure that you allow enough time for one schedule to complete before another starts. For example, if Exchange protection schedule 1 has DB verification and replication enabled, and it runs every hour, and Exchange protection schedule 2 has DB verification turned off and no replication, and it runs every five minutes, it is possible that without enough time between snapshots in schedule 2, schedule 1 cannot start.
Careful planning can greatly enhance your backup strategy. You may want to retain hourly snapshots for a few days to allow quick recovery, and retain only daily snapshots for longer periods, such as several weeks. You can define retention periods for snapshots. The Nimble-provided protection schedules have default values that keep volumes in the normal retention range, which is 150 snapshots or fewer, retained either locally or on the replication partner. Although you can configure volumes with a high snapshot retention schedule, it is not recommended. As you define protection schedules, a meter identifies when you reach the high retention range. A mouse-over tooltip identifies the ramifications of defining protection schedules that exceed the normal retention range.