Calculating Time Req'd for 1st Time Machine Backup

[tenbee]

Does anyone know where I can find the actual speed that Time Machine is using to backup my ext HD?

I purchased a 2TB ext HD (WD My Book) and I'd like to know the actual transfer rate... I know for sure it's not the reported 100 Mbps as promised by WD. I'm backing up about 440gb for the first time, so I know it will take a few hours at minimum... but I'm still curious about the possible actual time.

 

[Boyd01]

This app should give you a pretty good idea of disk performance. I think that figure will put you in the right ballpark.

https://itunes.apple.com/us/app/blackmagic-disk-speed-test/id425264550?mt=12

 

[Barney63]

I restored about 120GB from a time capsule over WiFi today and it took about 4 hours.
Using USB3 it would be far faster.


Barney

 

[Boyd01]

I clocked my new Time Capsule with my 2013 MBA on AC wifi at 28MB/s write and 30MB/s read copying large files from the Finder. That is not very much slower than my USB2 bus-powered Passport hard drives (~35MB/s). But if you have a USB3 drive it should be a lot faster. I have a couple inexpensive Seagate thunderbolt drives that clock around 180-200MB/s.

 

[hfg]

You could open "Activity Monitor", select the "Disk" tab and there will be a real-time graph at the bottom with the transfer rate to the right side (be sure "Data" is selected above the graph).

Select "Network" if you are transferring your backup data over WiFi or wired network to a NAS or Time Capsule.

The TimeMachine progress window will also give an "estimated time remaining" once it sees stable data transfer rates.

 

[chrisn123]

My experience is that Time Machine initial backups are NOT simply I/O bound. I see a mix of maxed out writing with a fair amount of MUCH slower traffic. I think a rule of thumb might be closer to 50% of "large file finder copy" I/O rate.

Also, make sure you quit all apps before backup. Time Machine backups seems to run at low priority and quickly yields to other tasks/apps, which can slow you down a lot.

Restores from a single initial backup, however, are much closer to "full speed," but still not totally I/O bound.