The cloud is displacing many established technologies, among them Network-Attached Storage (NAS) and Storage Area Networks (SAN), but it’s too soon to tell just how much of an impact cloud computing will have on the physical storage infrastructure market.

George Crump, writing for Network Computing, offers a vision of the future wherein SANs’ importance will greatly diminish, only used to facilitate the use of automatic tiering technology to quickly offload tier 2 and 3 storage and archived data to the cloud, leaving room for new or frequently accessed information. As the cloud’s reach becomes longer, SAN and NAS vendors and solution providers are eyeing its progress warily, but Network Computing’s Frank Ohlhorst believes there will always be the need for NAS and SAN technologies.

He argues that the cloud will evolve to become “a distinct storage layer, sitting between high-capacity, SATA-based tier 3 systems like virtual tape libraries, and offline tape archives.” Considering that enterprises are just beginning to be comfortable enough with the cloud’s security, reliability and accessibility shortcomings to use cloud storage for tier 2 or archival purposes, it’s probably going to be awhile before NAS and SAN technology is completely displaced.

Once the cloud can effectively be secured and uptime more firmly guaranteed, this situation may change, but for now, building a hybrid approach — SAN for high-speed, tier 1 storage access and cloud storage for everything else — is the most palatable for risk-averse enterprises.

These risks, as outlined by Dion Hinchcliffe at ZDNet, include: “Security of enterprise data that’s stored in the cloud, risk of lock-in to cloud platform vendors, loss of control over cloud resources run and managed by someone else, and reliability.”

The irony here is that even the most evangelistic purveyors of cloud technologies, storage vendors included, rely on SAN technology in their own data centers; they’re simply shifting the SAN market demand from the enterprise to the service provider, Ohlhorst notes. However critical SANs may be to enterprises, the days of onsite SANs may still be numbered due to the migration of other technologies and services into the cloud and to offsite storage infrastructure.

The upshot is this: as long as security, reliability and accessibility issues continue to be barriers of entry to the public cloud for Enterprises, SAN and NAS will remain a viable, necessary part of any data center, albeit in a different role. In addition, hybrid clouds are a perfect solution that allows you to take advantage of the benefits of both worlds.