Amazon Neptune Storage - Amazon Neptune

Amazon Neptune Storage

Amazon Neptune data is stored in the cluster volume, which is a single, virtual volume that uses solid-state disk (SSD) drives. A cluster volume consists of copies of the data across multiple Availability Zones in a single AWS Region. Because your data is automatically replicated across Availability Zones, it is highly durable, and there is little possibility of data loss.

This replication also ensures that your database is more available during a failover. This is because the data copies already exist in the other Availability Zones and can continue to serve data requests to the DB instances in your DB cluster. The amount of replication is independent of the number of DB instances in your cluster.

Neptune cluster volumes automatically grow as the amount of data in your database increases. A Neptune cluster volume can grow to a maximum size of 64 terabytes (TiB).

Graph size is limited to the size of the cluster volume. That is, the maximum graph size in a Neptune DB cluster is also 64 TiB.

How Neptune Storage is Billed

Even though a Neptune cluster volume can grow to up to 64 TiB, you are only charged for the space actually allocated. However, when Neptune data is removed, such as by using a drop query like g.V().drop(), the overall allocated space remains the same. Unused allocated space is then reused automatically when the amount of data increases in the future.

Because storage costs are based on the storage "high water mark" (the maximum amount allocated to your Neptune DB cluster at any time during its existence), try to avoid ETL practices that create large amounts of temporary information, or that load large amounts of new data prior to removing unneeded older data.

You can determine what the "high water mark" is currently for your Neptune DB cluster by monitoring the VolumeBytesUsed CloudWatch metric (see Monitoring Neptune Using Amazon CloudWatch).

If a substantial amount of your allocated storage is not being used, the only way to re-set the high water mark is to export all the data in your graph and then reload it into a new DB cluster. Creating and restoring a snapshot does not reduce the amount allocated storage, because the physical layout of the underlying storage remains unchanged.

For more Neptune pricing information, see Amazon Neptune Pricing.