I finally got around to purchasing and installing Little Snitch today. I should have expected this, but upon first launch (after rebooting the computer) Little Snitch went crazy with the snitchin’. A couple of quick tips to make this go a little more smoothly:

• You are going to have to choose to approve or disapprove many background processes, many of which request some pretty shady-sounding URLs. If you only approve them “Until Quit,” they will go into a list of “Temporary Approvals.” At this point, you can go through that list at your leisure, making the rules permanent, leaving them temporary, or denying them permanently as you see fit.
• Although Little Snitch comes with reasonable defaults for Safari and Mail, it does not come with anything for Chrome or Firefox. If your web browser of choice is launched on startup, create the same rules for it as already exist for Safari; this will save you a lot of clicking. Additionally, Mail does not come pre-approved for ports 80 or 443. When it tries to render HTML messages, you will see popups. If you already are OK with HTML messages, might as well copy those rules (open port 80, 443) from Safari over to Mail as well.

Hopefully this saves you some time and clicking.

If you have been sadly struggling with the new Apple Disk Utility software, I can confirm the instructions on this page work to restore the old Disk Utility. I can make no claims as to the reliability of running the old Disk Utility on El Cap, however.

https://justus.berlin/2015/10/restore-old-disk-utility-in-os-x-el-capitan/

Simple, but very helpful.

SATA hotswap drive in mdadm RAID array.

I usually am just swapping out failed drives, which is pretty simple when you are running a spare. However, to increase the size of the array I need to swap out otherwise healthy, running drives. An easy but nerve-wracking procedure.

Update 2015-12-12: The info in this post is no longer correct; you can now simply follow the instructions on this ubuntuforums.com thread, particularly this post on Dae’s blog to get Time Machine up-and-running. 😄

If you previously followed my instructions, to back out of the home-built netatalk, you can try the following:

sudo apt-get remove netatalk
cd /usr/local/src/netatalk
make uninstall

Then follow the instructions posted above.

My large file server once was able to act as a Time Machine provider over-the-air, back before Apple disabled the ability to use Samba shares as Time Machine disks. However, following a few simple instructions from these helpful folks below, I was able to make OTA Time Machine backups happen again.

• Installing netatalk on Ubuntu 12.04 from source
• Basic instructions for setting up netatalk Time Machine:

Thanks, Daniel and Pepijn!