TL;DR version:
Ottawa: Saved a prorated ~$190,000 by making the swap, and they get a 7th rounder for a guy who was on the taxi squad. I'm sure a lot of taxi squad guys on two way deals have their agent bugging their team's GM about moving them to a team where they could potentially collect an NHL paycheck, so Ottawa might have done Saros a solid if they weren't planning on using him.
San Jose: Traded an AHL D for a possible bottom pairing NHL D.
Anaheim: Swapped out a stalled prospect for decent AHL defender, the team will hopefully have a decent playoff run. As a bonus, they acquired the team captain's brother.
Edit: Didn't realize Trevor Carrick was a lefty D, was picturing his brother who shoots right. Maybe easier to run their maple syrup business together.