Creative Communities of the World Forums

The peer to peer support community for media production professionals.

Forums Storage & Archiving Best File Format for Backups

  • Best File Format for Backups

  • Todd Gruel

    July 28, 2020 at 7:32 pm

    Hi, all.

    I’m setting up a new backup setup now and I’m trying to determine the best file format to use. I’ll be using CCC to backup my MacBook Pro. I have a 7200 RPM LaCie d2 drive for my backups. I understand that backups can be done using either Mac OS Extended Journaled or APFS. I’ve heard dramatically varying opinions about the capabilities of each and I’m…confused.

    Some people have claimed that HFS+ is more reliable as it’s been around for 20 years and has more support so far from Apple. Some claim that it is less prone to issues and is easier to recover if needed. The downside of HFS+ is that I would be stuck using partitions; this isn’t a big deal, but it is a little more cumbersome to need to guess my future storage needs as I’ll be splitting the hard drive between Mac and Windows projects (unless partitions can easily be reformatted and resized later one? — again, this is something I’ve heard diverging opinions about).

    On the other hand, some people have claimed that APFS is faster and more reliable and works best when backing up a computer that is already formatted in APFS (which my MacBook is as it’s running Catalina). The potential downside of APFS is that others have claimed that APFS tends to be noisier when running on platter drives as the drive moves more erratically.

    I also understand that bootable clones can only be accomplished using APFS drives. This brings me to my bonus round question: What purpose do bootable clones serve if I don’t anticipate needing to ever work from my external drive? Since my MacBook has a 4TB internal drive, if I were to run a bootable clone, that could potentially take half the space of my external backup drive.

    Anyway, any thoughts on best practices for data management?

  • Patrick Sheppard

    August 4, 2020 at 8:21 pm

    Which version of CCC are you using? If v4, then CCC will read but not write to APFS (if memory serves, double-check that info if needed). If v5, then you’re good to write to APFS.

    I would backup to HFS+. I currently use APFS only on my boot drives, and that only because Apple requires it for boot drives on Mojave and later. If I had my preference, I would still be on HFS+ (as was the case when I was still running High Sierra). Not to say that APFS is unreliable, but HFS+ does have the advantage of being time-tested, tried, and proven.

    I’m still using HFS+ on volumes that are for file storage only. Until I’m convinced that APFS is mature enough — and until Apple releases full APFS documentation so that third-party utility software companies can implement full functionality in their products for diagnosis and repair of APFS volumes — I will likely continue to use APFS only where I have to.

    If you mean cloning a volume to another volume, then bootable clones are possible with both HFS+ and APFS. I’m a CCC user and the software does this very well in my experience. Bootable clones are very useful as backup boot drives. In my opinion this is a good practice, because it safeguards against potential boot drive issues that might otherwise cause downtime. In fact, I usually clone my boot drive to a dedicated boot backup volume and to a disk image prior to a major OS update (e.g. High Sierra to Mojave). After a major update, I also clone the newly updated boot drive to a separate disk image so that I have known good OS installs from both before and after the update. I tend to do these same backups about 2-3 times a year because of things that change on the boot drive over time (software updates etc.).

    Cloning your boot drive won’t result in cutting your disk space in half unless you already happen to have 2TB full on your 4TB drive, in which case CCC would warn you about having enough space for the backup anyway. That said, another good idea would be to get a second external drive for dedicated system/data backup. And that dedicated backup drive should be kept offline except when needed, for backups or for getting up and running quickly in the event of an issue with the primary boot drive.

    How do you intend to use the same drive for Mac and Windows projects? Will the external drive be physically connected to either computer at a given time? Or will the external drive only be connected physically to the Mac, for you to copy files from Windows to Mac over a network connection?

  • Todd Gruel

    August 5, 2020 at 9:51 am

    Thanks so much for the thorough response, Patrick.

    I’m using the latest version of CCC (although it’s a trial version). And I’m currently using Catalina, so my internal hard drive is APFS formatted.

    Because of that, others have advised me that it’s “easier” to keep using APFS for my external drives, too. I’ve confused though because I’ve heard such mixed messages from various people. (Obviously Apple will be biased and prefer the newer technology of APFS.) My understanding is that bootable clones are only possible on APFS drives — or at least using CCC, as that is what I was told directly by CCC support staff. Is that not the case?

    To that point, I’m still not convinced that I need or want a bootable clone. Is it necessary? I’m not too concerned about “down time.”

    Here’s my setup: I’m using a 4TB internal drive for my MacBook. I have two external platter drives for extra storage; one of them is dedicated for all things backup. I intend to do most of my working off my internal MacBook drive. But I may link some projects to media stored on one of my external platter drives — depending upon the workflow I establish (like music streaming — if I can figure out how to sync iTunes to my music library on an external drive — and possibly some video files). Mostly, though, the external drives will be used for either backup or for simple media use.

    My concern with bootable clones is that it’s all-or-nothing in the sense that you can’t pick and choose what you back up. If that’s the case, by the time I finish saving everything I want to save to my MacBook’s internal drive, I’ll have about 3.5TB. That’s a big clone! There goes a 1/3 of my external drive for backups!

    Solutions? If it’s highly advisable to use bootable clones (saving occasionally, before major updates) then I could get a third cheap platter drive dedicated to this purpose? But what exactly is a disk image? How does that compare to a bootable clone?

    As far as sharing drives goes for Windows and Mac, I’m still figuring that out. ☺ I want to keep this all as simple as possible. I’ll probably use a virtualisation software, so, if I understand correctly, I don’t need to worry about partitioning my drive between OS formats, right? If so, all media will share the same space (without need for partitioning in HFS+ or separate voluming in APFS). (If not, I’ll need to use partitions or opt for APFS volumes.) And the media will likely be saved to both my MacBook’s internal drive and to my primary external hard drive that will be used for extra media storage.

    Thanks for your thoughts as I’m working through this new workflow. I don’t want to change things around after I settle on a good system. Like you, I have some concerns about APFS, although it does seem more convenient…

  • Patrick Sheppard

    August 5, 2020 at 7:13 pm


    Apologies, I should have clarified: CCC does create bootable backups for both HFS+ and APFS volumes. However, for all macOS versions from Mojave and upward (which of course includes Catalina), a bootable backup of an APFS volume would have to be done to another APFS volume since Apple requires APFS for booting in these versions of macOS. So you and CCC support staff are correct about that.

    However, you can clone data files from one volume type to another. So if you wanted to clone a file storage drive to another file storage drive, and one is APFS and the other is HFS+ (or vice versa), then this can be easily handled by CCC.

    Bootable clones aren’t necessary. I like to use them for two reasons: 1) They’re convenient for having an alternate boot drive if I want to do maintenance to my primary drive that requires being booted from a secondary drive. 2) I believe having them is just prudent and a good practice to safeguard against issues.

    In order to avoid larger than necessary clones of the boot drive, you might look into creating separate volumes on your internal drive, keeping one relatively small volume for the boot volume and then another volume for file storage. Definitely research the best way to go about this if you decide to pursue it, so that your computer doesn’t lose data from adding or resizing volumes. Another solution may be to get a dedicated drive just for the bootable clone, as you suggested.

    A disk image is basically a backup of your volume (or data files) that is saved to one large container file, that can then be used to restore the backed up data to a volume. So if a volume had 100,000 files on it and you back up that entire volume to a disk image, then all 100,000 of those files would be cloned to a new location inside of a single container file that is an “image” of the disk. In other words, a disk image backs up files from a volume to a single file rather than from one volume to another volume.

    I believe you’re right about virtualization software and not needing partitions for different file systems used by different OSes, but of course it’s a good idea to research that to be sure.

  • Todd Gruel

    August 6, 2020 at 9:12 am

    Thanks for clarifying. That makes sense.

    So then the question remains: Is APFS worth it for the convenience of bootable clones alone? I could still dedicate part of an external drive to the clone, partitioning it in APFS.

    I’m still not convinced that bootable clones are necessary. I’ll also be backing my data up using BackBlaze. That’s a lot of redundancies.

    I like the idea of organising my internal drive in such a way to minimise large clone backups. I’ll look into that. ☺

    How does the disk image of a drive differ from having a bootable clone of a drive? Do both not copy the same files in the same way? Is it not redundant? Can you not have one without the other?

  • Patrick Sheppard

    August 6, 2020 at 2:47 pm

    APFS is worth it for bootable clones because Apple’s requirement to use it for boot drives makes it worth it, by necessity.

    Yes you can dedicate a portion of an external drive to a bootable clone. In fact you can have HFS+ and APFS volumes on one drive. I currently have that setup on one of my drives at home.

    If you’re not convinced to do bootable clones then that’s fine. You have to make your own decision there. It is a good idea though to at least backup your boot drive, whether you use CCC, BackBlaze, Time Machine, or some other program.

    A disk image is a file. A bootable clone is a fully functional volume. In order to benefit from the disk image, you have to restore it to a volume.

    So think of it this way:

    Bootable clone
    Volume –> Volume

    Disk image (cloning)
    Volume –> File –> Volume

    Disk image (backup)
    Volume –> File

    Note that ” –> ” represents the cloning action, using software like CCC or similar.

    So a disk image is the contents of the volume saved inside of a single file, which can then be kept as a backup of the volume and/or used to clone to a volume.

    Makes sense?

  • Todd Gruel

    August 6, 2020 at 7:11 pm

    Thanks for your help.

    I understand that it’s advisable to use bootable clones. I’ll continue considering it.

    But when it comes to disk images, can they ultimately accomplish the same thing but in a different way? For disk images, is the backup still comprehensive — are all system files and user data included? Or just essential system files?

    If I understand correctly, if there was an issue with my computer, I would need to take the time to “clone” the disk image back to my computer in order to resolve the issue versus working directly from the bootable clone on an external drive, right? If that’s the main difference, speed and convenience, then I’m not too concerned as I don’t mind a little “down time.” If there’s a significant different in stability or safety of my data then that’s a different issue.

    For clarification, when you say “backup your boot drive,” does this refer to a specific way of backing up or cloning a computer? In this case are just essential system files backed up? If so, this may be what I have in mind as I’ll be running other general data backups alongside this process.


  • Patrick Sheppard

    August 6, 2020 at 8:37 pm

    Disk image backups are generally complete whether you backup the entire volume or a specific folder (unless you tell the software to do differently). So backing up an entire boot volume to a disk image and then restoring that disk image to a volume will result in that volume becoming a bootable clone of the volume that was backed up to the disk image.

    Yes the main difference is speed and convenience between those two options. So if you don’t mind taking the time, back up to a disk image instead.

    I was using the phrase “backup your boot drive” as a synonym for cloning the boot drive.

    For more specific answers, I suggest consulting CCC’s online documentation, which is thorough.

  • Todd Gruel

    August 10, 2020 at 10:57 am

    Is the main difference that a bootable clone can more easily be updated as changes occur (changing only the files that have changed since the last backup) whereas a disk image must be recopied as a whole every time a backup is made?

    Is there any difference in file integrity and safety and security of the data between these two methods?

  • Patrick Sheppard

    August 12, 2020 at 3:30 pm

    Disk images can be updated.

    I don’t currently know the answer to the other question.

    Further info:

Viewing 1 - 10 of 10 posts

Log in to reply.

We use anonymous cookies to give you the best experience we can. Our Privacy policy | GDPR Policy