I am confused on how Time Machine works. I have an iMac with approximately 1 TB of "stuff" (i.e. data, apps, etc.) on my hard drive. I have a Time Capsule with 3 TB worth of available capacity. When using Time Machine it says there isn't enough space on my Time Capsule. What gives???
iMac 27″, macOS 10.13
Thanks, this really helps.
The screenshot of your iMac's hard drive reproduced again below confirms that you have 2.9 TB of data on the hard drive. Time Machine will try to back this up, but it can't, because you would need 2.9 TB of space plus another 20% or so for overhead.....(about .6 TB) for a total of about 3.5 TB of free space that needs to be available on the Time Capsule.
I'm not clear on exactly what the "Purgeable" entry really means, but the implication is that this is data that can be removed from the iMac's hard drive. If this is true, then Macintosh HD would have 1.18 TB of data on the drive and there should be be plenty of room for the Time Machine backup to occur........(although it is going to take a very long time for this to complete, probably 2-3 days).
No guarantees, because I have not done anything like this in the past. Good idea to make sure that the "purgeable" data really is purgeable before you proceed. Maybe this article will help:
Also might be a good idea to ask about the "purgeable" data in the Apple Support Forum for the iMac, which is linked below:
Thanks, this really helps.
The screenshot of your iMac's hard drive reproduced again below confirms that you have 2.9 TB of data on the hard drive. Time Machine will try to back this up, but it can't, because you would need 2.9 TB of space plus another 20% or so for overhead.....(about .6 TB) for a total of about 3.5 TB of free space that needs to be available on the Time Capsule.
I'm not clear on exactly what the "Purgeable" entry really means, but the implication is that this is data that can be removed from the iMac's hard drive. If this is true, then Macintosh HD would have 1.18 TB of data on the drive and there should be be plenty of room for the Time Machine backup to occur........(although it is going to take a very long time for this to complete, probably 2-3 days).
No guarantees, because I have not done anything like this in the past. Good idea to make sure that the "purgeable" data really is purgeable before you proceed. Maybe this article will help:
Also might be a good idea to ask about the "purgeable" data in the Apple Support Forum for the iMac, which is linked below:
Open Time Machine Preferences again, then click on Options
Look for the listing of Estimated size of full backup. What is the size listed there?
A screenshot of the entire Options window would really help. Example:
Unfortunately, the screenshots did not appear. Normally, when you take a screenshot, the file will appear on your Mac's desktop. To insert the screenshot into a post, click on the next to last image on the menu bar at the bottom of the reply window......to one that looks like two mountain peaks. Then using the Finder interface, navigate to select the screenshot that you want to include.
Once the image appears in the post, you can change the size of screenshot by clicking on it, then dragging on the handles at the corners of the screenshot.
If the message says that there is not enough space on the Time Capsule, there is probably not enough space for the data that you want to back up.
On your iMac......
Click on the Time Machine "clock" icon at the top of the Mac's screen
Click on Open Time Machine Preferences
Post back with the information about the Time Capsule hard drive
For example.......".2.7 TB of 3 TB available"
When you try to run a backup, what does the message that appears say?
Post back with the exact text of the message.
For example......."Time Machine requires xxxx of space and only xxxxx is available"
2.85 TB of 2.85 TB available. Waiting a complete first backup.
The backup needs 2.91 TB for the backup but 2.85 TB are available. Select a larger backup disk or make the backup smaller by excluding files.
The numbers say it all.
You have 2.85 TB of free space on the Time Capsule
The backup.......(there must be a HUGE amount of data on your Mac) will require 2.91 TB of space on the Time Capsule and only 2.85 is available, so it's a no go.
Note......Time Machine requires a lot of "overhead" space for a backup......up to 20-25%. So, the actual data on the Mac to be backed up might only be about 2.4 TB, but the extra overhead space requirement pumps things up to the 2.9 TB range. Nature of the beast.
I appreciate your assistance. Here's the numbers from Finder: Total hard drive capacity = 3.12 TB; Available 2.08 TB (1.87 Purgeable). So, I am really only wanting to backup the 1.04 TB (3.12 TB less 2.08 TB). But have 2.85 TB available space on my Time Capsule.
That is what will be backed up. You might have some other hard drives attached to the Mac that have not been Excluded from the backup.
In the example above, you can see the attached hard drives at my Mac that are Excluded from being backed up.
In other words, if you have any hard drives that are attached to your Mac.......and they do not appear in the list of Excluded items........then they will be included with the back up along with your Mac. That will really drive up the amount of data to be backed up.
If you don't want them to be backed up, you'll need to add them to the list of Excluded items from backups to keep them from being backed up along with your Mac.
A screenshot of your Options window would really help please.
I've included three screen shots that hopefully will assist you. Screen shot #1 is what you requested - Options window from Time Machine. #2 Finder screen shot of entire system. #3 Finder screen shot showing my iMac hard drive info.
Here's an update based on your previous recommendations. Thanks for the article on managing purgeable storage. I completed the article's second recommendation of using Terminal commands to create large files and then delete them in order to reduce the amount of purgeable data. It was a success. I had 1.94 purgeable capacity and after completing the Terminal commands it reduced it to 65 Gig. - a substantial reduction. The combination of the Terminal command procedure along with your other recommendations has solved my backup issues. Thanks so much for your assistance, recommendations, and patience!
This is my first time using Apple Community and actually first time in sending a screen shot, so bear with me if you have duplicate screen shots. Thanks so much for your assistance!
Using Time Machine
