NETGEAR RNDP6620-100NAS - ReadyNAS Pro RNDP6620 Business Edition Software Manual page 103

When a snapshot is taken, a duplicate snapshot appears in the browse list alongside the
original share, except the duplicate share name has -snap appended to the original share
name. For example, a snapshot taken of the share music is available as music-snap.
You can traverse a snapshot share just as you would a normal share except the snapshot
share is read-only. You can select a detailed listing to show the snapshot time in the
Description field.
Snapshots can expire when the reserved snapshot space is filled. The snapshot
mechanism keeps track of data that has been changed from the original volume starting
at the point when the snapshot is taken. All these changes are kept in the reserved
snapshot space on the volume. The Disk space utilization field on the Volume screen
shows how much space has been reserved for snapshots.
After the snapshot is taken, if changes on the volume exceed this reserved space, the
snapshot is invalidated and can no longer be used.
Note: Changes that occupy space in the reserved snapshot space include
new file creation, modifications, and deletions; for instance, any time
you delete a 1MB file, the change caused by the deletion uses up
1MB of reserved space.
When the snapshot becomes invalidated, an email alert is sent and the status reflected
on the Snapshot screen. The snapshot is no longer usable at this stage.
ReadyNAS for Business RAIDiator 4.2.17
Backing Up Your Data
103