Introduction to Cloud Storage

Cloud storage is an industry term for managed data storage through hosted network (typically Internet-based) service. Several types of cloud storage systems have been developed supporting both personal and business uses.

Personal File Hosting

The most basic form of cloud storage allows users to upload individual files or folders from their personal computers to a central Internet server. This allows users to make backup copies of files in case their originals are lost. Users can also download their files from the cloud to other devices, and sometimes also enable remote access to the files for other people to share.

Hundreds of different providers offer online file hosting services. File transfers work over standard Internet protocols like HTTP and FTP. These services also vary in:

◈ storage capacity and network bandwidth quotas
◈ network transfer speeds supported
◈ price (some are free or ad-based, while others are based on data usage)
◈ the software interface (some are browser-based while others utilize dedicated application clients)

These service work as an alternative to home network storage systems (such as Network Attached Storage (NAS) devices) or email archives.

Enterprise Storage

Businesses can utilize cloud storage systems as a commercially-supported remote backup solution. Either continuously or at regular intervals, software agents running inside the company network can securely transfer copies of files and database data to third-party cloud servers. Unlike personal data that is generally stored forever, enterprise data tends to quickly grow obsolete and backup systems include retention policies that purge useless data after time limits have passed.

Larger companies can also use these systems to replicate large amounts of data between branch offices. Employees working at one site may create new files and have them automatically shared with colleagues in other sites (either locally or in other countries). Enterprise cloud storage systems typically include configurable policies for "pushing" or caching data efficiently across sites.

Building Cloud Storage Systems

Cloud networks that serve many customers tend to be expensive to build due to the scalability requirements for reliably handling large amounts of data. The decreasing cost-per-gigabyte of physical digital media storage has helped offset these costs somewhat. Data transfer rates and server hosting costs from an Internet data center provider (ISP) can also be substantial.

Cloud storage networks tend to be technically complex due to their distributed nature. Disks must be specially configured for error recovery, and multiple geographically-distributed servers must typically be managed to cope with the high bandwidth requirements. Network security configuration aspects also require the expertise of professional who command relatively high salaries.

Choosing a Cloud Storage Provider

While using a cloud storage system brings advantages, it also has downsides and involves risk. Selecting the right provider for your given situation is critical. Consider the following:

◈ Cost. Vendors charge fees for at least their more advanced service offerings. Service plans may be divided into tiers according to usage, with penalty fees charged if you exceed the specified quotas. So-called "free" services can place serious restrictions (quotas) on the amount of data which can be stored in or accessed from the cloud. Carefully consider your storage needs before locking into a subscription: Buy enough capacity and capability to support you and your organization, and try to avoid long-term contracts that can cause serious issues later when your needs grow.

◈ Usability. Cloud storage systems should make working with remote data almost as easy as data on your local hard drives. Test out carefully both the user interface (browser or separate application screens) and responsiveness (network latency ) of a vendor's system looking for major time-wasting usability limitations that sap your productivity.

◈ Reliability and Reputation. Even a free cloud storage service can be costly if it suffers from frequent downtimes, loses or corrupts data, or has had past security incidents. Research the service providers you are interested in for reputation and their brand quality before committing to one. Consider also using a vendor's trial subscription before committing to a long-term investment with them (and do not load any particularly sensitive data onto a service during trial periods).