Caching data locally would consume quite a bit of bandwidth and take a massive amount of time if there wasn’t any intelligence into what is already cached locally. Deduplication and compression ensure only the elements of data that have changed are sent to local cache. If using the cloud as primary storage across multiple sites, global dedupe and compression can enable up to a 90 percent reduction in the total storage footprint across all sites.
File directory browsing must be as responsive as local network-attached storage (NAS). To do this, not only should the active data be cached locally, but the metadata of all files, not just cached files, must also be cached in solid-state drives (SSDs) at all sites. Without all the file metadata in cache, users think that their computer or network is running slow as navigating a folder is one of the most basic functions for a user.
5Support for ‘Chatty’ Applications
Applications must work as well across sites as they work at a single site. Many technical applications (CAD, PLM, BIM) are extremely chatty, which normally increases the time to open, save or sync a file from less than 30 seconds on a local NAS to over 20 minutes when centralized in the cloud. The reason for this delay is counterintuitive in that most people think it is a bandwidth issue when in fact it is a result of how chatty these applications are.
6Data Integrity and Cross-Site Locking
When data just lives on a file server, we only have to worry about maintaining one consistent copy (as long as the file is locked when a user is editing it). This changes when data lives in the cloud but is accessed across many sites. To avoid file corruption when using cloud storage, you need two things: a) a clear separation between the authoritative copy of data in the cloud and the local cache copy at each site, and b) granular component-level locking that works across sites and can lock portions of files rather than just entire files.
7Better Than Local Security
8Flexibility to Change
You never know when you might need to change cloud providers. Companies get acquired or go out of business—such as Nirvanix. You might also want to use two cloud providers, essentially using one as a secondary site. A global file system should support both scenarios.