Tip: The tool we recommend at the end of this article is going to save you a lot of time!

Moving files from a centralized server share, or large computer hard drive, into the Cloud requires planning. OneDrive for Business, like any business-grade Cloud storage, is not to be confused with Cloud backup. Here's a simply distinction:

  1. Cloud storage: for quick retrieval, addition and use of current business files
  2. Cloud backup: archiving of business files no longer in current use
If we lazily dump all of files on a local server/computer share onto OneDrive for Business we're going to suffer a big performance hit. For speedy, fast access to cloud data we need to differentiate between files that should be archived and files that are current.

Know your limit
There are some technical reasons why files will fail to sync to OneDrive for Business, such as invalid character and file types; you can read about the limits here: http://support.microsoft.com/kb/2933738. However, it's not practical to hunt out each of these files in advance so you may as well deal with them on a case-by-case basis afterwards. What is important is to understand the quantity and size limits. Here's the two key limits (as of Aug-2016):
  • Total storage: 1000 GB per user
  • Quantity: 20,000 items (files and folders) total, per user
  • Size: 10 GB, per file
  • Local cache: circa double the actual space*

In addition to per-user storage, SharePoint is included for the entire organization:

  • Total storage: 1000 GB for the entire organization (group folders, etc.)
  • Quantity: 20,000 items (files and folders) total, per library (a single library could be a shared group folder)
  • Libraries: Unlimited
  • Size: 10 GB, per file
  • Local cache: circa double the actual space*

Plan and organize
Let's suppose that we have a server share with 500,000 items. How do you fit that into 20,000? The pragmatic solution involves:
  1. Archiving
  2. Ownership
  3. Hardware upgrade

Archiving will take care of a lot of those 500,000 items. For example, is there an "IT Admin" folder somewhere? It probably contains a backup of some software installation CD/DVD - why not compress that into a single archive? If anyone needs the files, just copy the single archive to a temporary folder and extract. Whilst Microsoft operating systems have a native "Send To > Compressed (zipped) folder" function, you may want to use the free tool 7 Zip (see http://www.7-zip.org/) for lots of extra functionality such as high compression. Hunting around the folder structure you'll probably find folders named "Backups" or folders with date names such as "2010-2014" - these are already likely candidates for archiving.

Ownership of folders, when organized, can divide a large set of items. Once our 500,000 items has been archived down to less than 100,000 items we could divide that up among 10 users with an average of 10,000 items each. Remember, OneDrive for Business includes comprehensive sharing options; user "A" in Accounts and user "B" in Accounts can both provide shared access to their folders for each other, effectively doubling their quota. Once the users understand the limits and accept their responsibility to perform some house-cleaning then all you need to do is show them how to use...the right tool for the job - TreeSize

Hardware upgrade is a simple and economic way of providing workers with fast, local (cached) access to their files in the Cloud, especially for mobile workers who may not have complete mobile data coverage. Plan in advance so that such workers have suitable hardware in place. See note below*

Tool: TreeSize Free

Get yourself over to http://www.jam-software.com/treesize_free/ and download the latest version; alternatively there is an archived version attached to this article. Whilst Microsoft have always provided a way to search for large files (for example, http://social.technet.microsoft.com/wiki/contents/articles/19295.windows-8-how-to-search-for-large-files.aspx) there are numerous 3rd-party tools which make the task quick and simple. By far the fastest and simplest we've ever come across is TreeSize, which even comes in a free version. Take a look at this screenshot:

Key things to note: easily identify which folders contain large quantities of files, and target them for archiving. Also note the size being reported, which can assist to identify files too large to upload. Importantly this tool is simple and safe for non-technical users to use.

Staged migration

In a real setting, with an office server shared network drive and multiple users, there's no "push button" way of getting all this data into the Cloud using OneDrive for Business. You'll need to migrate in stages. Why not tackle the remote workers first, since they'll benefit immediately? Rather than "cut" the data from the network share, you may want to rename the root folder "Sales" to "Sales_MOVED-TO-CLOUD_Do-Not-Use". Copy all of that data to a host computer* and start synchronizing to OneDrive for Business; the root folder can be shared immediately so that coworkers have access to the files - whilst the data syncs they will have to liaise with the main coworker who now "has the data" on their computer, or perhaps download a copy of an original file and upload it into the OneDrive portal online via a web browser (at http://portal.office.com). Speed of network connection will often determine how this is staged.

Cloud backup of archived data

Someone in the organization (or sub-contracted) needs to be tasked with auditing the data on at least an annual basis. This assessment stage would be an ideal time to involve them in the process, so that the good work invested in this planning phase can continue into the future. A suitable Cloud backup solution will often augment Microsoft's OneDrive storage solution, ensuring that if the organization ever needs to access 2 TB worth of legal records from 10 years ago, it can be retrieved!

* Important note regarding local cache size: the Microsoft Office Document Cache is often equal in size the the actual size of the combined files residing in the local copy of OneDrive for Business. For example, a user with a OneDrive of 100 GB will need (1) 100 GB free space for the local copy of the files, and (2) 100 GB free space for the "Office Document Cache" (see https://support.office.com/en-ie/article/Office-Document-Cache-settings-4b497318-ae4f-4a99-be42-b242b2e8b692 but basically, each file is stored for 15 days - when you first sync this means that every file is going to get cached!). So if a user is going to use 100 GB of OneDrive for Business storage, they're going to need at least 200 GB free space on their computer.