By Lisa Coleman
Tacit Networks is tackling network-attached storage (NAS) problems such as scalability and the slow speed of remote file access by enabling the most current files to be shared among remote offices instantaneously. Other vendors are also trying to solve those problems, but Tacit is unique in its approach to storage caching, according to analysts.
"The idea is to cache a file at some place on the edge so that you can retrieve it more quickly," explains John Webster, senior analyst and founder of the Data Mobility Group. "It's similar to Web caching, where you click on an icon using your browser and instantly bring up a file."
Tacit Networks' technology enables file sharing over WANs via caching appliances and a tunneling protocol. Used together, a Tacit Storage Cache and Tacit Cache Server enable NAS traffic to run over WANs at near-LAN speeds, according to company claims.
In the past, it was not efficient to extend NAS over a WAN due to extremely poor performance because the standard NAS file-sharing protocols (NFS and CIFS) assume very low latency networks. When clients are linked to NAS over a high-latency WAN, there is considerable performance degradation.
NFS and CIFS are synchronous and "chatty" protocols that can be tolerated within a LAN environment but not over a WAN, says Tim Williams, chairman and CEO of Tacit Networks and former co-founder of CrosStor Software, which was bought by EMC.
Tacit Networks' Storage Caching Internet Protocol (SC/IP) tunneling technology mitigates the problems of running CIFS and NFS over WANs, according to Williams.
SC/IP converts CIFS and NFS for WAN transport and then back to CIFS or NFS for file sharing (see figure).
The Tacit Cache Server appliance sits in front of a NAS system and coordinates remote file access. The Tacit Storage Cache attaches directly to a LAN at a remote site and connects to a Cache Server through a gateway using standard VPN Internet connections. The Storage Cache appears to users as a local NAS device.
Tacit's storage caches are read/write devices, as opposed to Web caches that are read-only devices, according to Williams.
The Tacit Storage Cache and Tacit Cache Server are priced from $20,000 to $24,000 per node.