External storage for 2019 MacBook Pro

I’ve been putting this off for too long. I’m currently using iCloud storage optimization to optimize storage on my 2019 MBP, but have recently been convinced this is an absolute TERRIBLE idea.

Also, my only backup is an external Time Machine drive, which is not good enough.

I need some help from the groupmind about how best to improve the setup.

For regulatory and security reasons, cloud backup like BackBlaze is not an option.

What I’m thinking about doing is upgrading to three external drives:

  • One would be an overflow drive. This will probably hold archived materials, not frequently accessed. I may be wrong about that–I may end up using it for live documents And I may use it for photos, managed with the Apple Photos app.
  • The second would be Time Machine, backing up both the overflow drive and the main drive.
  • The third would be a redundant backup, backing up both the overflow drive and main drive, running Arq, Carbon Copy Cloner, or SuperDuper.
  • Can I get by on spinning disks or do I need the more expensive SSD?

Here are my questions:

  • Does the group have a preference between Arq, Carbon Copy Cloner, or SuperDuper? Or should I use something else?
  • How should I attach all these things? The world of USB-A, USB-B, USB-C, and Thunderbolt is a mystery to me–when people talk about such things, they might as well be talking Klingon. All I know about those kind of connectors are the shapes of the tips. I also know that some USB-C connections require power and some of them deliver power and if you guess wrong you’re out of luck.
  • Do I want to stick with USB-C drives, or can I use a USB-A/B drive? Do I need to get one of the docks that Gabe “Macdrifter” Weatherhead describes here?
    The CalDigit TS4 and OWC Thunderbolt Docks - Macdrifter
  • Is there anything else I need to think about here?

In a few weeks, I expect I’ll deploy a second Mac, network the two, hang one Time Machine drive off one and the other three drives off the other. I’ll back up each Mac to its own Time Machine drive, and then back up both Macs and the overflow drive to the SuperDuper/Arq/CCC drive. Will there be any problems with that?

Thanks! I am really a novice on these matters, which is one reason why I’ve been putting off this upgrade.

@MitchWagner OK, here are some thoughts, working through your posting…

  1. I am not sure what “regulatory” and “security” reasons would preclude the use of BackBlaze, given that any data leaving your computer is encrypted, but given that circumstance, would it be feasible for you to use Arq for cloud backup? As far as I am aware, BackBlaze cannot access your data, but perhaps there are other issues. Arq allows you to select where your data is stored online if that is an eg (eg you need a repository outside of US or EU regulations, for example) and similar provides you with data that is encrypted before it leaves your computer. I DO feel strongly that an off-site backup is a necessary component for any backup strategy.

  2. I think your breakdown of three external drives makes sense. Because you are, if I read your posting correctly, short of free space on the internal MBP storage, obviously you need some sort of supplemental storage. If the data on the external drive is data you do not need when on the go, an external drive works well. If it is data you might need access to on the go and carrying around the external drive and hooking it up is a problem, then a NAS that you can access locally and remotely might be a better solution.

  3. Agree that one external drive for TM and one for cloning is ideal. I would not place Arq, CCC, and SuperDuper! in the same category, and my approach is to have one external drive for TM (actually there is a TM store on my Synology and an external drive as a second TM store) and another (again a share on the Synology) for daily clones. I like to have both TM and a CCC clone (SuperDuper! is fine too for cloning) so that if one method of storing data fails I have another.

  4. I believe the clone and TM drives can easily be spinning drives, giving you higher capacity at lower cost. However, if the overflow drive is going to store documents, photos, etc that you will actively work on, I think you will find an SSD worth the higher cost long term. If it is truly for overflow that you use infrequently and you will not be carrying this drive around with you, then a spinning drive might be good enough.

  5. I use CCC, but my impression is that SuperDuper! is just fine as well, and I would not think you will have a problem with either. Both are different than Arq, which is for encrypted incremental backups but not cloning, and I use both CCC and Arq, with the latter going to the cloud.

  6. I would suggest USB 3.1 or 3.2, which means 5 or 10 GB USB. For 3.2 I believe you need the USB-C connector, while 3.1 can run over the USB-A or USB-C connectors, Remember that USB-C and USB-A are the hardware connectors, and USB 3.0, 3.1, and 3.2 are the data transfer speeds and protocols. Most external USB-C drives come with cables that are both USB-C and USB-A at the computer connection end, so connect to whatever port(s) you have available. USB-B is a different connector not used for external drives. I do NOT think the cost for a TB drive is worthwhile for you unless you are editing video from the external drive, so I would not go TB.

  7. You need a dock if you do not have enough ports on your laptop and/or connected monitor if any to connect all of the drives that you need connected simultaneously. Dock selection depends on your laptops ports and what you need to connect. I currently have the CalDigit TS4 and it works fine, and my guess is that if you want 3 external drives connected to a 2019 MBP you will need a dock. You could also go with a USB-C adapter that has multiple USB-A 3.1 or 3.0 ports on it just to connect the drives. I believe Satechi makes one, and possibly OWC and CalDIgit. I would have to look.

  8. “Is there anything else I need to think about here?” Yes. You should really think about an offsite strategy as well. I am curious as to the constraints that make it impossible for you to use BackBlaze.


Carbon Copy Cloner and SuperDuper are very similar products. Same use case, roughly the same set of capabilities, both seem to be well thought of by the MPU community. They’re intended for replicating one drive (or a portion of it) on another drive (or a portion of it). So either cloning entire drives or cloning specific folders off of a drive.

Arq is a very different tool. Think of it as more like a much more flexible version of Time Machine that can not only back up to a local hard disk or network volume, but also over the internet or to online storage services like Amazon S2. Like Time Machine, it backs up to more of an opaque database format, rather than replicating your raw file and folder hierarchy. However, like Time Machine, it will support things like file versions, etc.

Personally, I use both: Carbon Copy Cloner to a backup drive attached to my machine and Arq backing up to my home server (plus Backblaze, but I know that’s not an option for you).

In your position, I would probably say to get Carbon Copy Cloner or Super Duper, then use Time Machine. At least three drives: one for data, one to clone both your internal HD and the data drive using CCC, and one to back up your internal HD and data drive via Time Machine. Size the data drive based on what you need to store. Clone backup should be bigger than your internal HD plus the data drive. Time Machine drive should be 2-3x your internal HD plus the data drive.

You could buy a nice dock, but if you’re just getting it for these backup drives, you can get by with just a good USB 3 hub. SSD probably isn’t necessary for the backups unless you want to do a bootable clone (which is still doable with an Intel machine, for now). It may be more desirable for the data drive, depending on whether you’ll actually work off of it or will it be more of an archive,


Another thing to consider is offsite backup. I have a portable HD that I put in a safe deposit box in a bank. So if my house burns down, I still have this offsite backup to recover my data. I usually rotate once a quarter (OK, less than that, but that’s the ideal!)

1 Like

Excellent tips, all. Offsite backup is definitely on my priority list but not in the short term. I would hopefully like to get the onside backups sorted within 10 days, if not shorter.

You do t mention how portable your setup needs to be. Will the MBP be disconnected often? That can change the strategy.

As mentioned CCC and SuperDuper are quite similar. I’ve tried both and prefer CCC but it’s like Coke/Pepsi or Ford/Chevy. I prefer them over something like Arq because I can browse the backups easily with Finder and don’t need the enhanced capabilities of Arq.

This link describes the encryption that BackBlaze uses. That level of encryption meets HIPPA Standards and is usually sufficient for most sensitive data. Unless all your external drives are encrypted BackBlaze is more secure than them.

For backups any USB connection should be fine but USB-A 3 and USB-C will usually handle as much data as the drive provides. I boot an old Mac Mini off an external SSD connected via USB3 at far faster speeds than the SATA spinning drive.

I am not a fan of “Optimize Mac storage” since there’s no easy way to backup what you have stored there. I sync everything to iCloud but every Mac has sufficient space to keep it all locally so I can make multiple backups.

1 Like

Not much to add to the excellent points above, but CCC (Bombich Software) has helpful pointers on choosing backup drive, which should be generally applicable regardless of the kind of backup solution.


1 Like

Thanks, all!

Cloud backup is not an option.

Great article—thanks for sharing!

@MitchWagner I think this thread has great advice.

I would also recommend using SSDs for the overflow drive.

I’d recommend (ordered by speed + price):

Good: Samsung T5 (540mb/s)

Better: Samsung T7 or SanDisk Extreme (1050mb/s)

Best: SanDisk Extreme Pro or Samsung X5 (2000+ mb/s)

The “best” drives would likely be indistinguishable from your internal SSD. If you wanted to save some money, I think the “better” options would be great value.

I have an X5 and a T5 that I am using in a similar role, and if I were doing it again, I’d probably just end up with the T7 or SanDisk.

If write speed is of utmost importance, the X5 or another NVME SSD would be the way to go. (Not required for my uses, I’ve found out)


Good advice. I have a few of the SanDisk Extremes and they work really well for me. Note - when looking to purchase a SanDisk Extreme (not Pro) some vendors have the old model for sale. This model is slower by ~50%. Example for Amazon:

SanDisk Extreme 1TB model: SDSSDE60-1T00 - Read speed 550 MB/s - $175 (old version)
SanDisk Extreme 1TB model: SDSSDE61-1T00 - Read speed 1050 MB/s - $134 (newer model)

The page on Amazon for the old model does state that there is a newer model available but you may not see this. So just be aware to look the speed when looking for a SanDisk Extreme, don’t just look at the name. Newer model has a 61 before the dash in the model number.


Carbon Copy Cloner can now use the FSEvents service to get a list of folders that have been modified since a particular time, which can dramatically shorten the time needed to perform a backup. I haven’t been able to find the same capability yet in SuperDuper. Do you know if SD offers that option?

1 Like

It does. It was formerly called “smart copy” but is now called “copy changed files” or something of the sort. I don’t know whether it uses FSEvents or some other method to determine “changed”.


I don’t see any mention of FSEvents on the SuperDuper website, except in replies written by their users to their blog wishing that SuperDuper would use it.

“Smart Update,” "Copy Newer, and “Copy Different” are just what they call the typical approaches to making a disk backup, namely that they only copy the files that have changed. The rest of the data on your backup disk remains untouched. Time is saved by not copying unnecessary data. But they still have to read it all to tell if if has been changed.

The latest version of Apple’s FSEvents service lets backup apps register to receive notification when a folder has been changed on disk. This often gives a very short list of files needing to be written to backup compared to all the data on your drive, thereby speeding up the backup dramatically. Carbon Copy Cloner can use this service.


The MBP will sometimes be disconnected. I haven’t had to work outside my home office since December 2019. But I expect that will change at some point.

1 Like

Others have made excellent points here in this thread.

If you need speed then you can go with SSD drives. For some of these backup and archive purposes I have found that USB 3 and spinning drives are just fine.

I will make a full clone back up on carbon copy cloner every once in a while.

But also I use chronosync on a separate external drive - to copy my most important newly edited files / folders sometimes more than once a day.

Inexpensive choices…


I have the SanDisk Extreme Pro V2 and it is a great drive. Nonetheless, it only operates at up to 10Gbps on standard Macs; 20Gb/s requires USB 3.2 Gen 2x2 and Macs do not have the requisite hardware to take advantage of it (as I understand it); USB 3.2 Gen 2x2 support is “optional” under USB4.

Speed test of the Extreme Pro V2 on my MBP14

At first I tried to buy the original Extreme Pro to save some money, however those were no longer available. I am happy with the Extreme Pro and do not feel that I have spent money for a feature I do not use.

I back up my MBP14 with the Extreme Pro and CCC while on the move. It takes at most a few minutes even for tens of GBs, which is very convenient.

1 Like

I have a similar set up going. I have 2 external drives, 1 TB each. These are plugged into my always-on Intel Mac Mini. All my files sync between this Mac and my M1 MacBook Pro (my daily device), so I focus my backups on the Mini since its staying in place. One of the drives has my full Dropbox downloaded to it and the other one is a Time Machine backup. Since everything is always plugged in, I’m not particularly worried about speed. The drives are spinning drives and USB-A. Definitely saved a bit on the price that way!

Are you using an app (perhaps Chronosync or Resilio Sync …)? I plan to do something like this with my new Mac Studio and my M1 MacBook Pro. Maybe “locally” sync the Documents, Downloads and Desktop folders.

Are there any rules, exceptions or protocols you follow? I think that it would be unwise to sync your Photos Library, for example, because this might conflict with iCloud Photos sync.

Can you explain further about Dropbox? Are you allowing Dropbox to use its own sync for only the Mac mini? And are you syncing this Dropbox folder to the MacBook using your own “local” sync app, thereby avoiding Dropbox’s sync on the MacBook?

I actually use Dropbox for 99% of my files on both computers, just with its own sync system. Everything gets downloaded to the hard drive that’s attached to the Mini so the files can be included in my various backup systems (you just have to change the folder that its saving to in the preferences to move this from the computer’s drive). Then Dropbox keeps them up to date between that computer and my MacBook, plus iPad and iPhone. I’ll occasionally have files that sit on the Desktop for a little bit while I’m actively working on them, and I let iCloud handle those. Once they’re done, they get moved to the appropriate file in Dropbox.

Since my MacBook has 1 TB of space, I can’t quite put everything in Dropbox on it, and frankly, my archives don’t need to be instantly available on there anyway. I have my work stuff and files that I need regularly downloaded on the MaBook and just download anything else that I might need on demand.

I don’t use iCloud for long term photo storage. Since I only take photos using my iPhone, I let the Dropbox app use its Camera Upload process to add those into my Dropbox that Hazel (on the Mini) will file away for me by year/month. I’ll eventually just delete them from my iPhone after that. This is probably the weakest point in my current system, but photos are not a big part of my day to day, so I haven’t worried about it too much yet.

I would really like to use iCloud for more, but I’m just not happy with the sharing options yet. I’m the Librarian of a professional orchestra and I have to share large numbers of PDFs and audio files to various people, and Dropbox has been wonderful for that purpose. I’m also not happy that I can’t have iCloud download everything to an external hard drive and keep it up to date the way that I do with Dropbox. When its not downloaded, its harder to run back ups like BackBlaze.

So Amazon has the T7 for $109.99 and think I’m going to jump on it. Solid performance from your experience?