What is cloud-integrated storage and when should it be used?
Cloud-integrated storage (CIS) is the term used for SAN, network-attached storage and unified storage systems that tier and/or cache data to cloud storage. It is distinguished from a cloud storage gateway in two ways. First, CIS looks and feels like primary storage. This means it has the performance and functionality of a typical primary storage system, with the ability to deliver redirect-on-write snapshots, thin provisioning, storage pooling, hypervisor integration, data reduction (compression and/or data deduplication) and so on. It also performs similar to traditional primary mid-tier storage systems and, in several cases, it's similar to more recent hybrid storage systems (a mix of solid-state drives and hard disk drives).
The other major differentiator is the ability of CIS to represent from terabytes to petabytes (and a great deal more) of the cloud storage repository capacity as local data.
CIS is architected to tackle passive, cold or inactive data problems. Passive data represents as much as 90% of an organization's data and still requires rack space, floor space, administrators, and power and cooling. In the past, the cost per gigabyte (GB) tended to drop approximately 50% every 18 months based on density gains. But those density gains have slowed, along with capacity cost reductions, leaving many IT organizations in the lurch as data growth (with a compound annual growth rate of 62% per IDC and Gartner) continues to double every 18 months. This has brought storage costs for rarely accessed data to the forefront of administrators' budget planning.
Public cloud storage is meant to solve this cost issue. Public cloud storage is relatively inexpensive, ranging from 7 cents to 25 cents per GB per month depending on the number of copies stored in the cloud, geographic dispersal, resilience and so on. But two drawbacks to public cloud storage are the time required to get data into and out of the cloud and the need for some type of data mover. But many data movers do not deduplicate or compress data before it's moved to a public cloud storage repository, which can increase monthly costs.
CIS solves these cloud storage problems by caching or auto-tiering active data locally. It provides a storage administrator with configurable policies -- such as "last time since access" or "access frequency" -- that automatically move data to faster or slower storage as it transitions from an active state to passive or back again. While data is moved or migrated to a cloud storage repository based on policies (data value), it is presented as local storage to the user or application via a stub. CIS also moves and/or replicates snapshots to the cloud storage repository or repositories based on policy. No administrative intervention is required to move data from local storage to cloud storage.
Cloud-integrated storage enables content distribution to geographically dispersed sites without replication. Data resides in one or more cloud storage repositories but appears as local storage to the user/applications at multiple sites. Not all CIS systems can do this, but those that can make content or workflow sharing significantly easier and less expensive.
Public cloud storage repositories are excellent targets for passive low-value data, archive data and backup data. Cloud-integrated storage is an effective, painless methodology to implement one or more cloud storage repositories into the data center, bringing cloud storage to the user/application instead of the other way around.
BIO: Marc Staimer is the founder and senior analyst at Dragon Slayer Consulting in Beaverton, Ore. The consulting practice of 15 years has focused on the areas of strategic planning, product development and market development. With more than 33 years of marketing, sales and business experience in infrastructure, storage, server, software, database, big data and virtualization, Marc is considered one of the industry's leading experts. He can be reached at firstname.lastname@example.org.
This was first published in April 2013