Should I use an external drive for backup?

By | April 12th, 2016

exteranal hard drives and NAS RAID drives
If you’re already using Backblaze or another cloud backup solution, you’re well on your way to bulletproof data storage security. So why clutter up your desktop with an external hard disk drive and its bulky cable if you don’t have to? Well, there are still a few reasons to consider. Read on for details.

Primary backup

My backup strategy is to have both a primary and secondary backup system as part of my the 3-2-1 backup plan. The primary backup is the hard drive that sits on my desk. I’m a Mac person so I set up a Time Machine backup (software made by Apple, included with OS X) to an external USB 3 drive, which I connect periodically to make sure I have a timely backup. If you’re a Windows user, Windows has its own built-in backup software. There are plenty of other third-party apps you can install for either platform too.

Find out how to back up your Mac or PC with our Computer Backup Guide.

The advantage to using a hard drive as your primary backup is the immediacy of access. If you need to rebuild a complete directory or restore just a single file or document, it’s right there. You don’t need an internet connection or even a working network – just the computer, the hard drive, and the cable to connect them is enough to get your file back.

Figuring out what kind of hard drive to use is another story. Different computers have different peripheral connections. For a rundown, check out What’s the Diff: Thunderbolt and USB.


Restoring a file or directory is one thing, but it’s something else all together when the computer stops working because an essential system directory or library has gotten corrupted, damaged, or overwritten. Or when the computer’s primary boot drive fails, as hard drives sometimes do.

Interested in hard drive reliability? We use a lot of drives and have lots of opinions on the subject. Read our hard drive reliability review for 2015.

When you’re staring at a flashing question mark or a blue screen, you know you’re in for hours of troubleshooting fun. That’s hours of troubleshooting you can avoid with a clone. A cloned drive is a bit-for-bit copy of your regular hard drive. In the event of a major problem, the cloned drive can be used in place of the computer’s boot drive to keep you working.

External storage

Sometimes the amount of space you have on your computer’s boot volume just isn’t enough. Especially as more of us have gotten laptops, and companies have traded big hard drives for much speedier (but usually smaller) SSDs, we find ourselves with less and less space for the files we amass in work and life.

External hard drives make a convenient way to store those files without having to jockey for space on your computer’s boot drive. If you’re working with big data sets – video files, for example, multitrack audio, any kind of multimedia, large data sets that you’re doing analysis on, or any kind of archival, chances are you’ll want to put that on an external hard drive rather than relying only on what you can cram on your computer and put in the cloud.

Secondary backup

I’ll reverse the question I asked at the outset: If you’re already using a primary backup system, why bother with a secondary system at all? The phrase “don’t put all your eggs in one basket” comes to mind. Even careful management of your backup system won’t overcome the occasionally unforeseen and unforeseeable.

Backblaze is my secondary backup solution. I don’t depend on it exclusively to keep my files safe – but I know they’re there. And on the occasions I’ve had to restore files, I’ve gone to Backblaze more than once to grab something I either couldn’t find or couldn’t find easily with my primary backup.

Whether you use Backblaze, one of our competitors, or if you’ve cobbled together your own cloud backup system using Dropbox, Google Drive or other means, secondary backup provides you with a very important added layer of protection. If anything happens to your data and your primary backup system – even a natural disaster or a fire – keeping your data offsite in a secure datacenter is a good plan.

How’s your backup set up?

Enough about my backup routine. I want to know more about yours. Tell me how you’re backing up your computer. Or are you still confused? Have a question? Are we wildly off base and spewing out garbage info? Let us know in the comments. And if you have ideas for things you’d like to see featured in future blog installments, please drop us a line!

Peter Cohen
Peter will never give you up, never let you down, never run around or desert you. He also manages the Backblaze blog.

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Category:  Backing Up
  • Does Backblaze allow local hard drives or network drives as a backup destination? Or is it better to use something like CloudBerry?

  • trey

    I have file server at home that everything backs up to, I then back up the server to spideroak. I can’t consider Backblaze because I don’t use windows or osx.

  • Carol Anne Wall

    My laptop had a total meltdown almost two weeks ago. I received my new laptop yesterday. Thanks to Backblaze, my Seagate Back-up, and Dropbox, I was at least 66% restored within 12 hours. I have 100% confidence I will be fully restored in the next day or so — waiting for Dropbox to catch-up/sync and reinstalling some programs. The peace of mind is priceless.

  • Charles van Ouwerkerk

    Hi BackBlaze,

    I am a Mac user with an MacBook unibody 2009, upgraded with an SSD.

    I use a desktop hard drive for all my files, only OSX and some files on the desktop are on my Mac.

    I use Time Machine continuously on an extra harddrive for backup of ALL my files. I have a secondary hard drive for extra automated backup of all my audio, video and photos.

    I use a cloud service of 1TB for possible daily use of my document files, synchronised daily between my files hard drive and the cloud service.

    And above all, for the necessary peace of mind, I have been using Backblaze for a couple of years now for the event all my backup hard drives in my home would get lost due to fire, flood or another event.

  • Cindy Gabriel

    We want to upgrade our iMac from IOS Lion to El Capitan, but want to perform a cloning before we do so, just in case. We subscribe to Backblaze to backup our files, but want to clone as well. Could we also use Time Machine on the same external drive (we’ll probably buy a WD Drive)? Are we okay with the clone and Backblaze and nothing else? Thanks!

    • You’ll need a separate drive to clone on. Time Machine would be handy to have in case of emergency.

      • Cindy Gabriel

        So if we wanted to use Time Machine, we would need a 2nd external drive?

        • Yes, you need a dedicated drive for Time Machine. You can’t use the same drive for a clone and for a Time Machine backup.

          • Cindy Gabriel

            Thanks so much Peter!! Very helpful info.

          • Alex Stedall

            Couldn’t you just partition the drive, has one side for backup and the other side for Time Machine? – then do that with two backup drives X2 copies of backup and Time Machine.

          • No. Cloning is a bit for bit recreation of the target hard drive – it would destroy the partition map on the Time Machine drive.

  • Jonathan Alec Cross-Jones

    Mac user here. Ive converted my 2011 iMac to a dual drive with OS on SSD and working files on the internal HDD which is portioned so i have an internal clone of my SSD just incase of a bad update or system failure. All of my archive sits on a Drobo 4 Bay, and also house a synced copy of my working images folder from internal iMac HDD. A cheap external seagate holds a time machine backup of OS and i also have a portable clone of my SSD which sits in my camera bag when I’m away shooting a wedding all day. Ofcourse Backblaze backs it all up, but i wish there was an app for Synology.

  • usefulmusic

    I’m not a IT specialist at all but want to know if I can clone the system and some heavy applications onto an external hard drive to relieve the pressure on my 250gb Mac internal drive, which is clogging up.

    • Great question. Yes, you can. Should you? That’s more questionable. Using an external clone is likely going to be a lot slower than your internal drive. A better solution might be to offload what you don’t absolutely need for critical operations onto that external, instead.

      • usefulmusic

        Thanks for your reply, Peter. Trouble is I have already offloaded nearly every file. it’s the applications I use all the time that take up the space. So if it’s unwise to put the system on external drive, how about my putting most of the applications there? Is that possible and not too difficult? And will the applications – InDesign, Photoshop, Office, music notation and sequencing apps – function from the external drive?

        • “I have already offloaded nearly every file. it’s the applications I use all the time that take up the space.”

          Are you sure about that? Have you looked at the hard drive using DiskDaisy or another utility to see what’s using up space? I was surprised to find out how much stuff I still had on my boot volume that I thought I’d gotten rid of.

          Also, what kind of Mac is it?

          Most apps should work regardless of which drive they’re on.

    • Greg Zeng

      I’ve not used Macs; only Microsoft Windows & Linux. If the answer could address Windows systems please?

      On Windows, I found there are so many unnecessary files: cache, temporary, ethnic languages never used, backups created by applications, unknown to the user, etc. Windows has many third party cleaner applications, which are usually free. Many files can be further “compressed”: execution files and lossy compression sometimes. Other similar data files can be group-compressed into archival storage, to be uncompressed as needed.

      Windows allows whole drives or partitions to be NTFS-compressed as well. These partitions are similar to the “7z” open-source compression, but are read-write usable to both Windows & Linux. I assume that Apple can use the Windows-NTFS-compressed partitions too? And that Apple has other tricks that we have in Windows?

  • Cookie Dough

    Thanks for these helpful posts!

  • Aitor Bleda

    My strategy:

    1.Sources on external git.
    2.Primary backup: external drive, near the computer.
    3.Secondary backup: external hard drive inside fire proof safe. (Safe has a USB+power connection).
    4.Program to test file integrity of all files using a DDBB and a checksum.

    My wife:

    1.Primary: Backblaze.
    2.Secondary: external drive. Never used.

    Oh, and she has the hdd setup on raid w/stripping, so if one is bad, she loses all the data.

    My guess is, backblaze is good enough for most people.

  • Michael Smith

    I follow a similar strategy:
    * Acronis TrueImage with a weekly full/daily differential scheme on my all of my family computers to a 9TB NAS. I’ve had to restore images more than once due to HD failures or Windows completely flaking out.
    * FreeFileSync to sync directories between my desktop and laptop (i.e., ensures both have local copies of files) This is an older process that I could probably just replace with dropbox, though it has the added advantage of copying data to my desktop drive for Backblaze to pick up.
    * BackBlaze on my desktop with a continuous backup schedule.

    I recently added Amazon Cloud Drive thanks to a free 365 day trial to use for my media server content. Files are manually uploaded (just drag & drop), but that’s fine since it’s static content and I don’t see a need to bog down Backblaze with 1.5TB of MKV files.

    • Aitor Bleda

      I use acronis and google drive, + backblaze.
      I also have a file integrity database that checks tha unmodified files (by date) keep having the same hash.

  • Yendor

    Due to a very unreliable and often slow broadband service in Indonesia I prefer local backups. I use two external USB 3 HD’s. One a CCC bootable clone and one a Time Machine backup for my 512Gb MacBook Pro.
    T.M. is good for incremental backups which I do daily and the bootable clone twice a week.
    This gives me the ability to replace a lost or damaged laptop almost instantly by booting my wife’s (or another) laptop from my clone and the instant file restore capabilities afforded by T.M.
    My photos are stored in iCloud Photo Library and my music via iCloud Music Library for convenient use across devices.

  • I’m less worried about the files on my laptop, cause they’re either synced on Dropbox or code projects that live on GitHub, but I keep all the important files like my photo collection, archives of past projects etc. on a NAS I built myself (a Raspberry Pi with Samba connected to an external drive) that I’d like to keep safer than it is now. The plan is to set up duplicity on it with a Backblaze backend. Perhaps adding another local backup layer would be good too, which I’ll probably do when I upgrade the NAS to something like Synology in the future (and then use the Pi as the primary backup and Backblaze as the secondary backup).

  • freelyn

    Encrypted mount point on 3.5″ hard drive, full backup, stored in remote location. NAS backup of key files in basement, USB drive backup key files, and finally Backblaze.

    I’m not losing all my family photos and videos.

  • Dan Filipi

    Windows backup and Apple Time Machine backups to a WD Mycloud 4 tb network drive.
    Everything backed up daily incremental off site at 2 places, one is Backblaze.

  • Søren Ferling

    Libraries (Windows) mirror to Onedrive and sync to other machines with Onedrive – ~ 30 GB data.

    Other data, docs, media, archive, mirror to Backblaze, Jottacloud and Keepit – ~ 5 TB data.

    No local backup.

    Maybe in the future i will buy a usb-disk of the cheap archive-type from Seagate to local backup.

  • In 25+ years of supporting Mac users, there are 10 things we’ve learned about backup strategies.

    1) There is a perfect ratio between the complexity of a backup system and it’s failure rate. The more complex it is, the more likely it is to fail or remain unused.

    2) If you have 2 automated backup systems, one local, and one cloud based, you are better off than the over 95% of your neighbors.

    3) Apple is not a backup company. iCloud is not a backup system. It’s a syncing system that happens to back up most of what is on your iDevices, but only if you specifically instruct and pay it extra to do so. Macs are only partially backed up to iCloud, no matter what you do. It’s convenient for syncing and easy access, but it’s not a backup system.

    4) TimeMachine is the ideal backup system for most Mac end users. If you have nothing else, it will likely recovery your data 98% of the time. The other 2% of the time, a good cloud based system will save your bacon.

    5) No backup system is foolproof. Fools and non-fools alike should have some redundancy built in and attempt to understand if your data is being backed up by any means.

    6) No matter how often you tell people that hard drives are very convenient, but very unsafe places to store data, they will still say, “But it worked just fine yesterday…”

    7) No matter how often you tell people that hard drives can die at any time, old or new, they will still think of backup like that diet they really should go on to lose the extra 20 pounds (okay, 30 pounds) they packed on since college. People don’t understand that it is as crucial and as complicated now as learning how to read your gas gauge on the car you drive every day. (my wife says it’s more like 40 pounds…)

    8) That notion that if your hard drive is too full, you can safely move your entire photo library to an external drive instead of installing a larger internal drive is patently false. You will forget what is on that external drive, neglect to back it up, and/or drop it on a non carpeted surface experiencing a campy, special effects kind of heart-stopping, shattering sound.

    9) The frequency of your backup plan says precisely how much data you’re prepared to part with, even during tax season. If you back up once a week, you are saying to the Universe, “I can definitely afford to lose a week’s worth of data. Go ahead. Do your worst.”

    10) 87% of most statistics are made up.

  • Phil Isensee

    Windows User
    Macrium Pro image copy nightly to external drive (4 copies in rotation)
    Also multiple users files synced between machines with BitTorrent Sync (mostly for usability but provides backup, even off site when the tablet/laptop is away from home)

  • For now I use TM, CCC (is an immediate current clone), and back blaze. Have just under 30K photos.

  • SomeGuy2398067

    The primary backup is the hard drive that sits on my desk. I’m a hipster douche fag person so I set up a Shadow Copy rip-off backup (software made by crApple, included with OS Turd) to an external USB 3 drive.

    I fixed that for you.

  • Antonio Chinnici

    I would like to choose BackBlaze (business plan) as my secondary back up, but I won’t do it for two reason: you don’t do a back up of my NAS; you erase data after a month the external drive is disconnected from my machine. The B2 solution it’s not right for me. The business plan miss a little to be really perfect for me! I’m disposed to spend more than 5$ per month to have it.

  • karl

    [Computers] –>

    [NAS Sever – mirrored disks / shadow copies x6]

    –> [Offsite encrypted]

    –> [AWS]

    –> [Pen Drives Important Data]

    –> [HDD cold storage]

  • Joshua Evan

    Mine involves:

    2 full system clones (Thunderbolt drives – drives rotated weekly – drive disconnected when not in use)
    1 full system clone with file verification (Thunderbolt drive – run weekly – drive disconnected when not in use)
    1 backup of all images/photographs/illustrations (RAID1 USB2 drive – run monthly – drive disconnected when not in use)
    Crashplan – all user files, images, Mac settings etc (versioning, continuous)
    Backblaze – default Backblaze backup (continuous)

    I feel pretty confident with this setup, however am always keeping an eye out for new ways of keeping my data safe.

    • karl

      What’s the “default” mean next to Backblaze?
      Nice backup system.

      • Joshua Evan

        Default configuration – files that are included/excluded.

  • My main working machine (maxxed out 2009 Mac mini) has a 1TB external drive connected to it and uses Time Machine. I’ve been running the same setup for a couple years, so I have at least 1-2 years worth of data to fall back on. I’ve even migrated the entire Time Machine backup between drives to make sure it’s on a fresh drive.

    I also use Backblaze and have it backup everything, including my Dropbox & OneDrive folders; the latter is where I store my photos.

    I don’t bother with backups on my MacBook Air as there’s nothing important on it and the same goes for my Windows PC which is mainly for games which can be redownloaded easily.

  • fiddlergene

    I have an iMac for my heavy duty work and a MacBook Pro for my travel needs. I’m a photographer so I work with many thousands of files that are around 50mb. I put my photos onto a Drobo 5D (more on that in a moment) and my photo catalog on my internal HD. My internal HD gets backed up to an external Time Machine drive. My iMac HD and my Drobo get backed up to Backblaze. The MacBook Pro, which I use when I travel, gets backed up to Backblaze and whatever photos I shoot also get backed up to an external Passport HD. I feel pretty safe with the whole setup except that I don’t gave a clone, as you suggested.

    Now about that Drobo. I’ve had problems with 2 housings so far, and to Drobo’s credit they’ve stood by their warranty and replaced them. But after the second replacement – which came with its own set of headaches – I am looking for an alternative. Originally I liked the redundancy of the Drobo system, but now that 6TB drives are reasonable I’m thinking to one as my main photo drive and do I-don’t-know-what with the Drobo.

  • Steve Eshom

    I do something similar to what you describe Peter. My family has a couple of Macs in the house and we all use Time Machine. TM has saved us a couple of times including one machine that had to be completely restored. In additional all the Macs run ChronoSync to back up their data files to a local HD. Our last line of defense is the additional copy of everything going to Backblaze. Safety first when it comes to data!

  • jess huiz

    Mine is a bit odd, and may be overkill. boot HDD=SSD. data=normal HDD. Backup to 2 externals, these have a lot of larger files on them so they backup each other (plan to figure out offsite) and they both also backup to a 3rd HDD. My data i can’t replace is backed up to google drive, and MS drive.

    It’s not real easy to maintain, but I work in I.T so figure practice what i preach.