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Database Options for When SSMs Open New Albums
The table below describes the database options for controlling when an SSM closes one album and starts adding snapshots to a new album. NuoDB recommends that you use the default settings for these options. The following considerations might help you determine when it makes sense to change an option setting:
nuodbmgr prune snapshotscommand identifies one or more albums that can be removed. Removing an album will make all the snapshots it refers to unavailable for hot copy and restore. Consequently, you want to ensure that an album can be open for a length of time that is appropriate for generating the number of snapshots that you would want to remove as a group. See Freeing Storage Space Used by Old Snapshots.
Sets the minimum length of time that an album must be open. After this length of time, the SSM can start writing snapshots to a new album.
Sets the maximum length of time that an album can be open. If an album is open for this length of time then an SSM stops writing snapshots to that album and starts writing snapshots to a new album.
Sets the minimum number of snapshots that an album must contain before it can be closed.
Sets the maximum number of snapshots that an album can contain before it must be closed.
In an album, this is the maximum ratio of old record versions to current record versions. If the addition of a records atomThe internal object structure representing all data and metadata in a NuoDB database. Atoms are self-coordinating objects that represent specific types of information (such as data, indexes, or schemas). Atoms are stored in memory on both TEs and SMs or serialized over the network and stored to disk by SMs. See also Storage Manager (SM). to an album crosses this threshold, the SSM closes the album and begins writing snapshots to a new album.