Time Machine Drive Questions


(Jack Clay) #1

Hi,

My system: iMac (Retina 4K, 21.5-inch, Late 2015), 16GB, 1 TB Fusion Drive, High Sierra (moving to Mojave soon)

My backup system:

  • 2TB Time Capsule using Time Machine
  • 1TB IOmega USB external drive using Time Machine and SuperDuper
  • 500GB OneTouch USB external drive using SuperDuper

The Iomega backup drive is full and I’ve ordered a WD 4TB drive recommended by the Wirecutter. The imminent arrival of the drive brings to mind several issues that I’m sure members of this list can help me address.

  1. Is is possible to move the time machine backup file (Backups.backupdb) from the Iomega drive to the new drive so I can preserve the backup history on the new drive? If so, what’s the best way to do it?

  2. I plan to format the WD drive before using it. Because I will be moving to Mojave, and I understand my Fusion Drive will be converted to the new file format (HPFS?), should I format the WD drive using the new file format? If so how can I do that before I install Mojave?

  3. I think I’d rather have SuperDuper backups on separate drives (at least virtually) from the Time Machine files. Is there any reason not to partition the new WD drive into two ‘drives’ to keep things separate? (I realize a physical drive failure would doom both, but I do have the IOmega and OneTouch drives to use for SuperDuper, and the Time Capsule will still have the Time Machine files.)

Thanks for any thoughts!


(Simon) #2

I think the external HDD can remain HFS+. That way you’re not forced to go to Mojave. Once you have Mojave and you’re comfortable you can always switch to APFS to get its benefits over HFS+ on the HDD.

I would also prefer my clones on a different volume than my TM backups. In fact, I usually tend to keep them on different disks, but having them on the same disk (with two different partitions) has the added benefit that it makes the “TM disk” bootable, which it otherwise by itself would not be. If you chose a little over 1 TB for the clone partition on your new HDD, that will easily be enough for a full clone of your 1 TB fusion drive while leaving ample space for your TM backups. If you plan to never use all of that 1 TB fusion driver you can chose to partition a bit tighter.

I recall moving one TM backup from an old small HDD to a new big drive. I remember cloning it to the new disk with DiskUtility and then simly making sure TM was set up to use the new disk. Worked just fine. I kept the old small disk around to be sure, but I’ve never had to go back to it since. If you’d prefer to do it through manual copy rather than cloning, Apple has extensive instructions here:


(Alan Forkosh) #3

Note that a Time Machine Disk must cannot be formatted as APFS. See https://support.apple.com/guide/mac-help/types-of-disks-you-can-use-with-time-machine-mh15139/mac

For my laptop, my primary backup disk is a 2TB Seagate portable drive partitioned into a 1TB Carbon Copy Cloner clone and a 1TB Time Machine (the laptop has a 1TB SSD). Note4 that the clone is somewhat incomplete as I don’t clone the photo and music libraries (since they are extracts from the versions on my desktop). Every week or so, I plug the drive into my laptop and perform the CCC Clone. The Time Machine, of course, kicks in automatically. When both are done, I eject the partitions and disconnect the disk.

I should note that when I travel, I carry a 4TB HDD partitioned into a 3TB drive with a clone of my 3TB desktop (copied from the latest nightly clone) and a copy of the latest laptop clone. This is useful in 2 ways:

  1. If I need a copy of a file from my desktop while traveling, I can copy it from HDD.

  2. Should my home become inaccessible, I could recover my computer status by purchasing and working with new hardware (pusing that further down the list of concerns in that circumstance).


(frederico) #4

Backup strategies are like lasagne recipes; everybody has their own, and fights can get started depending on who’s in the kitchen on Sunday morning.

My longtime issue with creating two partitions on one Drive for backups is that both end up requiring/using unused disk space, and learning you’re staring at hundreds of GB of wasted space down the road is frustrating. Deciding to resize later can often be a big pita, if you don’t have yet another big fat drive to p,at swap-it.

Saying that you have a 1TB System Drive, and presuming you should thus have a matching (or greater) clone volume ignores actual current and future disk use, not to mention archiving features for the clones.

If you only have 129GB of System and data on your Mac, why burn a 1TB external volume for a clone (unless you want a huge depth of archives, especially for very large files which change minimally)?

Time Machine, likewise, tends to go into “Sorry, Dave, I’ve perceived an undescribed error I cannot repair, and I’m unwilling to let you repair it, either, so I’m leaving you no option but to nuke your last two years of carefully curated incremental backups and start from scratch.” -Mode the more often it bumps into a full disk and is forced to prune older backups to make room.

Given the $ choice, it’s one drive for clones (and temp manual backups/storage/data transfer games) and one for Time Machine. But to this day, I have no problems whatsoever allowing TM and CCC to share a single volume/drive, with storage limits and generous pruning settings for CCC, and, of course, protection set for root items. And I skip backing up most System/app data via TM, because it’s covered perfectly by CCC; I’m only interested in its hourly, incremental, easy to use user data restoration features.

If you do decide to split one drive for TM/Clones, be sure to put TM on the first partition, despite being faster and a normally a better choice for the clone (in case you need to emergency boot, a clone first is way faster to boot/use), because it’s far, far easier to resize a drive if you don’t have to erase/restore the TM volume.

To that end, if you can afford to leave the existing too-full TM HDD alone and just preserve it as an archive, and it’s easy enough to just pull out to access that old data if required, I’d advise starting a new TM backup from scratch, for two big reasons: one is the aforementioned “screw you, Dave” issue; it’s nice to know you can always drop back several months/years, despite random TM farts; two, it can take DAYS to transfer a TM volume to a new one, depending on interface speed and drive speed, and once you start, you’re committed; no restarts or interruptions allowed, lest you begin again — and no TM backups can occur in the meantime.

Once you’re confident that original archive is no longer needed, you can then repurpose that drive; indeed, it sounds like a nice size match for cloning, to begin with. In that case, why not devote the new 4TB to TM, with a temporary clone volume racked on the end; run that for a short term; then nuke the old TM, make it your SuperDuper drive, and zap the temp clone partition and let it fill out as a deep TM. Or continue with two clones and keep one offsite, etc.

We generally have at least two lasagna here, sometimes three, depending on the veggies in attendance.


(Richard Rettke) #5

For my needs, I found the best solution for Time Machine is a 15TB JBOD (Just a Bunch of Drives) setup (could be discrete drives but I have 3 5TB drives in a 4 bay ProBox enclosure). I started with 1 5TB and when that filled and TM cried “more, more”, I decided to start fresh with 2 5TB drives in the JBOD configuration. When 10 TB was insufficient to hold a years worth of backups, it was easy to add another drive to the JBOD.


(Adam Engst) #6

I agree about the single drive—I have one partition for SuperDuper’s bootable duplicate that’s the same size as my internal SSD and another that’s much larger for Time Machine to use over time.

On the other hand, my bootable duplicate is just that, an exact duplicate with no attempt to maintain versions. And then Time Machine is a complete versioned backup without anything excluded so I can’t make a mistake and exclude something I actually turned out to want later.

It’s extremely unusual for me to have to go back in Time Machine more than a day or two for a versioned backup and even restoring from Time Machine at all is something that happens only a few times a year. So I personally don’t stress about losing old versions if I have to reset Time Machine for some reason.


(frederico) #7

I’ve been shocked how many times I’ve had to go back a year or more, if not for myself, for family users who use their machines less frequently, and thus don’t necessarily even notice when something disappears or is corrupted; e.g., seasonal items, such as holiday lists, projects, files, etc., and especially, for some reason, email and the odd disappearance of tracks from iTunes now and again (I run a check for MIAs at least twice a year, and at least once per year, I have to use TM to restore a missing track).

Without incremental, historical archives, it’s very easy to know you had something last year, but only have a corrupt or missing version this year.

Since I keep my System drive separate from my Users drive, it is very easy to tell TM to ignore my System, and only backup my data, thus saving space and time.