Time Machine query after SSD swap

[Peter Franks]

I had the 320GB HDD in the MBP and backed up to TM. Now I have a 500GB SSD in the MBP, Time Machine now says,

but it used to just erase the old back ups automatically, and replace with the new ones.

The TM external is 500GB and the internal is now 500GB, so why won't it just write over it?
Also, My internal says 200GB is free, so only 300GB are used on the 500 SSD so don't know where it gets 352 from. What gives?
[doublepost=1526478471][/doublepost]I've just deleted the whole drive, and it's now backing up 291GB after saying it needed 352GB.
God this stuff confuses me! Anyway, it still makes no sense to me why it wouldn't just delete old one and write new one.....

 

[hobowankenobi]

TM. It just does that.

There are likely a whole bunch of things it detected as changed after the swap, and wanted to replace them...and did not have enough room.

The best fix is always be sure that your backup drive is more than double the size of the data set. 3 or 4 times is much better. Don't forget the whole point of TM is to have versions of files....so you can go back in time and restore multiple/different versions. Wiping and starting over does resolve this, but you lose all your history, and, your data is naked (without backup) until the first TM run is complete.

Simple math: in order to have just 2 backups of all files, you need about double the space. The goal is to have multiple versions....to have history. That's what TM does, and we don't get much say in how it does it, beyond excluding non-essential things we don't want to waste space on.

The ratio of available space to what is being backed up is the key. Shoot for 3-4 times (minimum) to have good restore points, history, and not fight the out-of-space nag.

If you just want a single, most recent backup, then TM is the wrong tool. You should look at some of the great third party tools that let you pick exactly what you backup, how often, and how many versions you want to keep. CCC, SuperDuper, Get Backup Pro...the list goes on.

 

[Peter Franks]

Thanks, before I deleted this TM, and it's now finished after many hours... it had around 4 back ups I think, dating back to 2011, because it always deleted and renewed on a 500GB external, from the 320GB HDD. I always expected there to be dozens of back ups going back years.... Wrong! Now they are 500 internally and externally. So you think I should get a 1TB minimum external just for TM. The Capacity/Available/Used on the newly installed SSD is fluctuating a bit without reason. Available is 197 at the mo, When I had the 320 in there, it was always near the knuckle on 300 plus. CCC is what did the SSD for me, and you have a good point, it was good, despite 5 hours for 270GB copying, but can't complain. Is SuperDuper so different? or Backup Pro?

 

[hobowankenobi]

Based on price alone, I would l suggest somewhere between 1 and 3 TB. You will see there is not much difference in price. The more space, the more history/versions possible. Don't forget to factor in that as the live data set grows (you create or save new stuff), the backup up space has to grow too....and at a higher rate (again, to have many versions).

You can still do an occasional clone to the existing drive, for added redundancy, and to re-task it. Some free tools will wipe and clone, while a host of paid tools will clone AND do incremental backups, which is much faster—only replacing what has changed, not starting over each time.

So:

• Disk 1 (small): bootable clone (a snapshot of the entire disk, done on your schedule (weekly, monthly, etc)
• Disk 2 (large): Automatic TM (continuous, versioned backup to cover recent changes and have versioned history of unique data)

CCC is probably the best tool out there, if you are paying for backup software. SuperDuper is fine too, and they have a free limited version that does clones nicely. The full paid version does timed and scheduled stuff too, similar to CCC. Get Backup Pro is aslo good, perhaps not as feature rich, but all the essentials plus more, for 20 bucks. There are more options, including Chrono Sync and Tri-Backup that are fine too....the list goes on.

 

[Peter Franks]

Good advice, thanks for that! Really good idea having the clone along side TM