CLARIFY HOW TIME MACHINE WORKS APPLE. PLEASE

salamastra44:

Perhaps your Mac needs a new and larger capacity external USB storage set-up for use as Time Machine.

At least 4GB, and depending on the Mac system version, the correct format (or default) for TM may vary.

Could be the external drive used as backup, may have acquired issues; & those may fail without notice.

The basics have not changed all the much, the following can be helpful; as it was nearly a decade ago.

• Apple OS X and Time Machine Tips | by J. Pond ©2013

http://oldtoad.net/pondini.org/OSX/Home.html

Following recent 'multi-system version' Support article, shows info from various macOS.

You can [choose/select] yours from the header; as details change too.

• Time Machine Troubleshooting on Mac - Apple Support (mojave + other)

https://support.apple.com/guide/mac-help/time-machine-troubleshooting-mh15653/10.14/mac/10.14

• If you need to create a new backup from Mac

• Connect a new backup disk to your Mac

Other ideas are available from help viewer, or search support; among other sources.

Since these are Apple Support Forums and Not Apple directly - to service your needs and to be constructive - suggest sending Apple your comments Directly to Apple via FeedBack and / or Get Support Start now and open an Apple Ticket.

salamastra:

Yes, was supposed to say at least 4TB. My smallest ones,

used to backup 500GB system partitions, are 2TB to 4TB.

However 'forced-timeouts' due to ASC site issues, make

my times online (here only) unpredictable. ..And shorter

than ideal, when trying to Edit. ~ Then ASC is unresponsive.

I've four backup USB, & two FW drives; (2TB & 4TB) for use

as system Time Machine backups. ~ And others, for Clones.

Since one of my mac desktops has two 1TB drives; both

partitioned in halves; an under-utilized original Server.

Initial new backups to USB Time Machine drives take

much longer duration. Later, little content gets added.

[Sorry for the technical problem, out of my control, which

contributed to an uncorrected reply in this ASC thread.]

To further add - the reason that Apple says that Time Machine works that way is because Time Machine works that way. If it isn't working properly for you, that means that you have a problem or conflict with some other app. That is not apple's fault. Yes, you should open a trouble ticket and get the problem resolved. Also, just so you know, when you type with all caps, that is considered to be yelling. It is also more difficult to read. I hope you are able to get your problem fixed.

sorry for the all caps! I was shouting as i was typing out of frustration 😅

but this is still not clear to me.... either time machine overwrites old files with new files and thus it should never tell you that it

is full.... or as I continue to read on google searches when the disk is full Apple says you must either delete files or replace the full disk. Both should not be true. My time caspule was not backing up for many months on mojave and now I have a brand new 1TB HD and am running Big Sur and the Disk is already "full" after less than a week and time machine will not erase old files with new files.

thanks! message is:

Time Machine couldn’t complete the backup to “Mac Mini Backup”

The backup disk needs 86,97 GB for the backup but only 49,91 GB are available. Select a larger backup disk or make the backup smaller by excluding files.

new 1TB HD installed a week ago... last backup was on June 17th

salamastra wrote:

thanks! message is:

Time Machine couldn’t complete the backup to “Mac Mini Backup”

The backup disk needs 86,97 GB for the backup but only 49,91 GB are available. Select a larger backup disk or make the backup smaller by excluding files.

new 1TB HD installed a week ago... last backup was on June 17th

1 TB for the Time Machine backup destination disk? The Time Machine backup disk should be at least 4 times the size of the disk being backed up. Otherwise you can run into the situation where Time Machine is unable to make enough room for the new incremental backup, hence the full disk. 90 GB is a huge incremental backup. Do you have large video libraries being modified frequently, or one or more virtual machine files being backed up? Just logging into a virtual machine often means the entire file for that virtual machine is "changed" and hence must be backed up. For very large files and folders, you might consider excluding those from Time Machine backups and just copying them periodically (once per week) manually to a separate backup storage location.

thanks for your help! Did you mean to say 4TB drive instead of 4GB? My Tech who works at an Apple Authorized reseller advised me that a 1TB disk should suffice as my 2TB mac mini has only 700GB of storage used at this time... Could be that he advised me incorrectly, and now I am looking at a new disk to toss only to buy another larger capacity.... but my problem is that Time Machine stopped backing up months ago to my time capsule with messages that disk was full.... so NOT erasing old files for new... and now with brand new disk and upgrade to Big Sur... time machine is still not erasing and replacing.... if Time Machine is designed to function that way the disk should never get so full that it stops backing up.... this is my frustration.... what is it APPLE? "the oldest backups are deleted when your disk becomes full" (and time machine continues to function) OR is it that time machine stops working when the disk is full 😅

I have NO idea what large files we are regularly changing on this mac mini... the only thing it might be is our dropbox files maybe. I will need to check if they are all still physically on the hard drive or if I already booted them to cloud only... I have already given up and ordered a 5TB disk to use.... thanks for the suggestions

But If this Mac Mini has a 2 TB drive, then I should have an 8 TB backup for Time Machine? !!!!!... My Apple rep REALLY did not understand this when he said a 1TB would be more than sufficient based on the data stored on my disk now

Rule of thumb would be 4x the size of what is being backed up. If 700 GB is used at this time, 3 TB is recommended, but your space used on your Mac will grow over time so it will need more backup space.

Your Apple Rep gave you poor advice, 1 TB backup when you are using 700 GB to be backed up is woefully inadequate.

Time Machine does not store each backup as a separate chunk. It only copies over new or changed files, and then links those to the unchanged files so that the disk, as configured on a given date, can be restored (or individual files from a given date can be restored). It also deletes older backups first when more space is needed. So if the oldest incremental pieces are relatively small, it may be unable to make space for the newer larger changed files by deleting older files. Normally it can do this, but if things don't fit, it gives you that message about the disk being full. This is more likely to happen if the backup disk isn't several times larger than the disk being backed up.

salamastra wrote:

I have NO idea what large files we are regularly changing on this mac mini... the only thing it might be is our dropbox files maybe. I will need to check if they are all still physically on the hard drive or if I already booted them to cloud only... I have already given up and ordered a 5TB disk to use.... thanks for the suggestions

But If this Mac Mini has a 2 TB drive, then I should have an 8 TB backup for Time Machine? !!!!!... My Apple rep REALLY did not understand this when he said a 1TB would be more than sufficient based on the data stored on my disk now

You can get away with smaller drives. A 1 TB drive will work, at least for a while. Eventually any Time Machine drive is going to flake out and need to be reset. But the smaller the drive, the sooner that will happen. If you follow that 4x rule, then chances are that the hard drive will physically fail, or become obsolete, before Time Machine flakes out. If you opt for something in-between, like 3x of used space, which for your 700 GB of used space would be a 2 TB drive, then you might get a year of backups before you need to reset.

Unfortunately, you do need to be careful with new hard drives. Some of the new hard drives use funky new storage systems like "shingled" recording to get very large capacities for very cheap. The emphasis here is "cheap". For these kinds of drives, you can expect physical failure long before Time Machine flakes out. Plus, they are glacially slow. Unfortunately, people experience this when trying to do a backup, so they blame Time Machine for being slow.

Works as expected on my system, did you click the little red information icon to see if it offers insight as to what is going on?

MtD

Additionally, please don't use all caps. It's considered shouting and rude. Also it's harder to read.

ok thanks

yes i was shouting and rude.... thought i might be speaking directly to APPLE

Apologies to all!!