Cloud Storage

Cloud storage is a component of what we generally term as cloud computing. By its very nature, cloud storage might reside in a remote geographical location, and this means that the response time for an application, the round-trip time (RTT), must be carefully considered.

Generally, organizations use the tiered storage architecture. In its simplest form, this implies the following tiers:

- Primary storage, having the highest performance, fast access, high I/O.

- Secondary storage, with emphasis on high capacity, not on performance.

Can cloud storage be used as primary storage?

So, the question arises if small and medium-sized businesses (SMBs) could use cloud services for their primary storage. Depending on your requirements, you can analyze if using a cloud storage service for primary storage would be a good idea.

The biggest drawback of this solution is the possibility of great variations in storage response performance over the network. The response to read-write requests might get slower, meaning that sometimes the round-trip times might be unacceptable. Packet loss over the network adds up to the response time due to retransmissions.

Generally, even for Microsoft Office applications, the cloud storage used as primary storage can perform poorly. Also, in case of Web applications, cloud providers might exhibit a wide variation in website performance, according to the geographical location. In some cities, end-user response times might be as much as 10 times slower than others. These are the most important argument against using the cloud storage as the primary tier, especially when slow applications affect the employees productivity.

For organizations, a major concern is also data security and data ownership, together with compliance regulations.

Online storage and types of data

Unstructured data

An argument for using cloud storage is the need for basic online data storage of unstructured data like user files. The benefits here are starting with lower overall storage costs. There is no need to buy storage hardware, thus data center storage costs are reduced. If the organization is leasing the data center storage, the hassle of refreshing the equipment every three years or so can be eliminated by using the services offered by an online storage provider, while still getting the benefits of up to date technology.

For unstructured data, there are many vendors to choose from depending on the service-level agreement (SLA) requirements and type of access.

Structured data

If online cloud storage is to be used as a long-term data archiving platform for various data structures in the enterprise, the number of vendors options are drastically reduced. In this case, the vendor must offer features like search and data lifecycle management. You must be looking also for the ability to store both unstructured data, and structured data like email or databases.

When to use cloud storage services?

An organization can look at using Software-as-a-Service (SaaS) such as Google Docs, or Microsoft Office 365, and store the applications data in the cloud storage provided. In such cases, the data storage is located together with the applications themselves in the same geographical location.

The round-trip response time is the same as in the case when the application and storage are local to the organization, and the online storage does not constitute a bottleneck. In this case, the only concern is the quality of the Internet network connection from the particular business to the online provider, as packet loss and outages independent of the online storage provider could appear.

In conclusion, you can use a Software-as-a-Service (SaaS) scenario, which has the advantage of offering cloud storage in the same external location as the applications themselves. Using online cloud storage as primary storage will provide poor performance and the use of a cloud data storage provider is not a good choice.

Cloud storage should be used for backup, archive, and storage of data which is not accessed very often, and is not performance-critical.