Friday, September 23, 2011

SkyDrive: 25 GB of free storage that's too annoying to actually use

For several years, I've known that I have a Windows Live SkyDrive account with 25 GB of free storage. However, I never actually tried to use it. Today I tried to use it and I see what's the catch: it's too annoying for storing large amounts of data.

I was hoping to upload all of my photos. Theoretically, it seemed like a good idea. The photo viewer is great, the per-file size limit is not an issue, and the overall size is more than other free services allow but only a fraction of the 25 GB limit.

The first problem is that the web uploader is quite limited. It can't upload folders, so I would have to manually create them and upload their contents. It doesn't even support drag and drop, except for in IE. Since uploading would be a lot of work, I rejected this option.

Then I learned that SkyDrive can be accessed via WebDAV and mounted as a drive in Windows. (It uses proprietary Passport authentication, so I'm not sure if any other clients can access it.) This was easy once I sorted out some firewall issues. Unfortunately, only document file types can be uploaded. Attempts to upload JPEG images and archives result in an error telling me that the file "is too large for the destination file system". It's not a file size issue because it happens with small files. I guess Microsoft only wants the WebDAV access to be used for Office documents.

Since PDFs are supported, I thought about using using them. JPEG images can be included in PDFs without re-encoding, and PDFs also support attachments for other file types. However, this is a kludge without any benefits besides WebDAV access, and so I decided to try ordinary multi-part archives instead.

Archives can be uploaded via the web interface, and files of 104,857,600 bytes (100 MB, 100 * 2^20) may be uploaded. Unfortunately, this is unreliable. The Silverlight uploader only seems to allow one 100 MB file to start uploading in a batch, and even that file seems to stop before the end. The upload seems to complete successfully, because the downloaded file is bit-identical to what I uploaded. The classic form based uploader also fails before the end, and I'm not sure if it's usable for large files.


Boris Gjenero said...

In IE 9, the Silverlight uploader successfully uploads 50,000,000 byte files. A large number of files can be uploaded via drag and drop, without any problems or additional user intervention.

I don't know what's the actual limit for reliable uploading of multiple large files. I know that 75,000,000 bytes is above the limit, and a binary search could find the limit.

Don't use Firefox. The Silverlight plugin crashes a lot when trying to upload.

Boris Gjenero said...

Directories can be downloaded as zip files, but this is unreliable for huge directories. It can work for up to around 2 gigabytes. To excessive and annoying retries, I recommend directories with 1 GB or less.