Q: What to do if your giant Time Capsule initial Time Machine backup is extremely slow
I had a 3 TB Fusion drive in an iMac with a 3 TB Time Capsule and a 2 TB external USB-3 drives for backup (dual backup and one for offsite).
When I got to 2.02 TB on the iMac the Time Capsule announced it was full due to two laptops also using it and the external USB drive ceased backing up too. I evicted the laptops, got them their own external backup drives, and attached a 3 TB disk drive to start a new backup on the iMac. It initially estimated 23 hours to complete, stalled in the 80 GB range, gradually climbing at about 2 GB per hour. I left home for 4 hours, for some reason Back To My Mac failed so I couldn't monitor this, returned home to find it had completed and had no idea of the tempo of the backup.
I chose to make another 3 TB USB-3 drive backup for offsite backup, attached it and started the Time Machine backup, this time checking on it ever hour or two initially. It did the same thing, got to 80 GB or so then slowed way down at the 2 GB per hour again, sometimes even slower. The next morning, in the 90s. The next day in the 95s. The third day it cracked 100 GB. At this rate I calculated it would take about a month? I consulted Applecare and went through a number of machinations I had already tried to no avail. I decided to start it again and wait it out just like I did with the first one because I had to leave.
It started really going at the 120 GB and it was done in about day after that.
So what to do with a very slow backup with a large amount of date? Perhaps just wait it out and if it's at least making progress it might just accelerate so don't give up.
For what it's worth, most data is a lot of video and photos.
Mitch
iMac (27-inch, Late 2012), iOS 6.1.2
Posted on May 3, 2016 3:34 PM