Data Management Glossary
Cloud Storage Gateway
A cloud storage gateway is a hardware or software appliance that serves as a bridge between local applications and remote cloud-based storage.
A cloud storage gateway provides basic protocol translation and simple connectivity to allow incompatible technologies to communicate. The gateway may be hardware or a virtual machine (VM) image.
The requirement for a gateway between cloud storage and enterprise applications became necessary because of the incompatibility between protocols used for public cloud technologies and legacy storage systems. Most public cloud providers rely on Internet protocols, usually a RESTful API over HTTP, rather than conventional storage area network (SAN) or network-attached storage (NAS) protocols.
Gateways can also be used for archiving in the cloud. This pairs with automated storage tiering, in which data can be replicated between fast, local disk and cheaper cloud storage to balance space, cost, and data archiving requirements.
The challenge with traditional cloud gateways which front the cloud with on-premise hardware and use the cloud like another storage silo is that the cloud is very expensive for hot data that tends to be frequently accessed, resulting in high retrieval costs. Read the blog post: Are Cloud Storage Gateways a Good Choice for Cloud Data Migrations?
Cloud Storage Gateway versus File-Level Cloud Tiering
Cloud storage gateways create a new appliance (virtual or physical) that acts as your storage at each site to cache data locally and put a golden copy in the cloud. They are useful when you are doing active file collaboration across multiple sites and do not have NAS at branch sites or do not want to use your existing NAS. But, they do not leverage existing data storage investments and require data to be moved to the gateway which creates additional infrastructure costs. Cloud storage gateways store data in the cloud in their proprietary format. Similar to storage-based cloud tiering, cloud storage gateways create proprietary lock-in and unnecessary cloud gateway costs in perpetuity. And they also typically create additional on-premises costs.
Cloud Storage Gateways: Additional On-Premises Infrastructure
Cloud storage gateways are typically hardware-based since they have to serve hot data from the cache. Many vendors also offer virtual appliance options for smaller deployments.
Duplication of Data in the Cloud
Cloud storage gateways typically put all the data in the cloud and then cache some data locally. So, if you are using a cloud storage gateway for 100TB, then all 100TB of data is in the cloud and a subset of it (maybe 20TB or 30TB) is also cached locally. This means you may need 130TB of infrastructure to house 100TB of data. Depending on the size of the local cache, this may be larger.
Cloud Storage Gateways: A New Storage Silo
A cloud storage gateway is a new storage infrastructure silo that caches some data locally and keeps all of the data in the cloud. It replaces your existing NAS. It does not work with it. It is a rip-and-replace approach.
Cloud Storage Gateway Licensing Charges to Access Data in the Cloud
Cloud storage gateways lock data in the cloud with their proprietary format. This means you cannot directly access your data in the cloud—data access needs to be through the gateway software in the cloud. Many customers are surprised to learn they have to pay gateway licensing costs even to access data in the cloud, and this cost continues as long as you need your data. This lock-in limits flexibility and creates unnecessary cloud expenses. It also limits your use of the cloud as you cannot natively access your data without the gateway software.
Assuming $700/TB/yr. of cloud storage gateway licensing costs, cloud storage gateways have 287% higher annual costs than using a file-level data management solution with the cloud. This is a recurring cost that you pay for over the lifetime of your data!
This table summarizes the common cloud data migration requirements and the differences between Komprise Elastic Data Migration and Cloud Storage Gateways.