Moving targets
Shooting down the problem of moving files on network shares requires finesse
FOR THE HUNTERS out there: No, we are not talking about venison this week. The moving targets we refer to are the files your users keep on network shares — thousands of word processing, spreadsheet, and database files, not to mention technical diagrams, blueprints, and CAD documents.
So, what’s the problem? In a word: relocation. Sooner or later space or performance concerns will require moving those files elsewhere.
Moving files to a new location means users have to map their client machine to a different network location, which requires some coordination with the storage administrator. Moreover, those “user files” often are as critical to business as a customer or an inventory database, so forbidding access during the move won’t do. Therefore, administrators have to schedule relocations for nonbusiness hours, an option that won’t be feasible if the night shift is not long enough for the move or if the files are accessed around the clock over the Web.
Rainfinity, a relatively new entry into the storage marketplace, may have a viable answer to this challenge with Rainstorage, although the initial release will only handle Linux or Unix shares.
In a nutshell, Rainstorage is an appliance that, using NFS (Network File System) copy logic and a virtual LAN to host the target shares, manages the copying of files from one networked volume to another. When the administrator initiates the copy, the appliance intercepts users’ I/O operations and redirects them to the proper location. A user’s write (or read) command directed at file A will be dispatched to the source location if the copy operation has not yet started, or to the new location if the copy is in progress or is complete.
Interestingly, in the last two scenarios Rainstorage also replicates the write operations to the source file, ensuring that for the duration of the copy, files on both shares will be identical at any time. Moreover, Rainstorage doesn’t lock the whole file but only a small 8KB chunk at a time, making the copy operation transparent and painless for users and administrators.
Hang on, Microsoft users. Last week, startup Arkivio launched its storage management software that uses a policy-based engine to determine what data should go where. Dubbed “auto-stor,” the software — for Windows environments only — first collects information about storage resources, then moves storage around according to company-defined rules. The idea is to put the right data on the right resource, based on cost and performance considerations.
By the way, you better get used to hearing about this policy-based storage concept. All the vendors are talking about it, including Hewlett-Packard, which last week outlined its road map for technologies that will better automate storage resources. But that’s another column.
