Tuesday, July 16, 2013

Tuesday's Tip -- Dropbox and Protected Invisible Files

Editor's note: Today's post was written by Richard Hanson.

As a genealogist, you realize the importance of access to your electronic data when and where you want it as well as having a copy backed up to a remote location safe from floods, fires, burglars and spilled drinks. There are a large number of Cloud-based online services (both paid and free) that can accomplish both. One of the more popular ones is Dropbox.

I use Dropbox for two purposes – sharing data with others and as an off-site backup for data files. It is the later activity, backup, about which I made an interesting discovery while researching some perplexing Dropbox behavior. test

Most of my data to be backed up by Dropbox is on an external drive that is a backup-duplicate of my data drive. To make that external drive part of my Macintosh's Dropbox, I used a Unix  "ln" command to create in my Dropbox folder a symbolic link pointing to the external drive. For Windows, you can do the same with either the MKLINK or junction commands. How to do both of those actions is posted at many places on the Internet.

This linking approach worked but had an unintended consequence. Both the Macintosh and Windows systems maintain invisible folders on hard drives intended for system use only. When Dropbox attempts to sync and/or backup these folders, it is blocked from doing so by restrictive permission codes, Dropbox lists the problem folder names in its log saying "access denied."

Dropbox log displaying a problem file.
In such circumstances, Dropbox never gets to the green "all done" state. Instead it remains in the blue syncing state by continuing its futile attempt to access those files. But this is more annoying than problematic. It uses very little system resources while doing so.

It turns out that you can tell Dropbox to exclude folders from sync and backup. Open up the Dropbox preferences window and select the "Advanced" panel. Then press the "Change Settings" button. A file selection window will be displayed (as per below on my Macintosh). Uncheck the folders that you don't want to be backed up or sync'd. Then press the "Update" button to save your changes. 

Telling Dropbox not to touch a specific folder.
On a Macintosh the names of these invisible folders usually start with a dot (e.g., ".Trashes", ".Spotlight-V100", ".TemporaryItems"). But there are exceptions like "Desktop." Generally speaking, the contents of these hidden files pertain to the drive they are on and do not contain anything that you would want in a file backup (or sync).

Alas, it was not going to be that easy for me. Dropbox continued listing the problem file in its log and never reached the all-done (green checkmark) state. I tried deleting the files in Dropbox's local cache – didn't help. I tried unlinking and relinking my computer – made no difference. Then I unchecked the external hard drive (i.e., told Dropbox not to access it). That worked! After doing a considerable amount of "indexing" Dropbox ended up in its all-done, green checkmark state of bliss with an empty error log. I then check-marked the external drive's box and Dropbox spent a lot of amount of time indexing and downloading. But it eventually again attained the all done state. But there were consequences. My backup software (using the "smart" backup option) decided that all the files in the Dropbox-managed external drive had changed. So it recopied everything. That, in turn, triggered Dropbox to do a lot indexing and uploading. But it eventually all worked out and Dropbox is currently working fine.

Note: At the time I was performing the activities described in this article, I was using Dropbox version 2.2.3 running on a Macintosh (OS X 10.8.4).

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