High Sierra - HDD recommendation and Time Machine Backup


macrumors member
Original poster
Sep 9, 2014
I am upgrading to High Sierra on Mac book Pro mid-2010 model having 1 TB SSD.
My time machine is on 1 TB 2.5" hdd
I am getting conflicting details about HDD for High Sierra.

Could you recommend
1) External HDD ~ 8 TB (I like HGST but confused on which model / features - there are so many)
2) Internal drive - SSD (want to upgrade to 2 TB)

And what to do with existing time machine ... will it recognize automatically or I should convert to APFS?



macrumors 6502
Nov 30, 2013
Keep TM disk as is, it will be recognized and re-used. In my case same TM disk is used by HS as was used by Sierra. HS just asked if to use it and backups continue, I can go back to February in my backups and restore files (this disk started in February).
You cannot use APFS on TM disks for now - they are NOT compatible with TM. No hard links. TM disks must be HFS+.
You should NOT use APFS on spinning disks, which I assume your TM disk is, anyway. For now use on SSDs only. And even that may be optional, unless installer forces it on its own.
If you upgrade to 2TB SSD system drive, you should get larger TM disk. Actually, to use TM as real backup, you should always use larger (few x) disk for TM than all disks combined being backed up'd. I use 5TB spinning drive to backup 1.5TB of drives (for months now and still empty space available).


macrumors 6502
Nov 30, 2013
Whichever is on sale and biggest you have money for. It is close to impossible to keep up with ever changing models of manufacturers and by the time we find out about reliability of a specific model, they do not make them anymore. And newer models may have different reliability. Personally, I gave up and decided to have at least TWO TM disks for each computer. I buy cheap enclosures and put in "internal" disks. If something fails, I can replace just the part. Buy two cheaper disk/enclosure combos and use both - the chance both systems will go bad - at the same time - is sufficiently small. TM software will switch between multiple disks on its own.
And ideally, have them in different places - like have one home and one at work. Encrypted.


macrumors 6502a
Jan 17, 2012
Rancho Bohemia, California
I use the two TM external drive approach as well, but simply buy two inexpensive external drives and rotate. Internal spinners are used for daily project backups; TM is the automatic backup of those backups.
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