Tag Archives: Storage

Q&A: A Fail-proof Data Backup Plan

(This post is from an email conversation with a friend. I thought the content might be useful for others.)

Q:  I want to back up my mac and presently have the time machine doing it. I think I remembered you telling me I needed another backup in place as well. Any recommendations on what and how to do that?

A:  I will suggest a perfect world solution, and a second one that has only one flaw.  All of this is based on the statement I made to you:  “If data doesn’t exist in at least three different places, it doesn’t exist.”  Optimally, three places means three different places on the planet, with at least one place far enough from the others that there is no reasonable possibility that a natural or man-made disaster could destroy all three.

(Yes, there are cloud-based backup solutions (which implicitly address the remote backup requirements) that cost less up front and require less management, but the big problem with them all is they require either a very fast upstream internet connection (most internet connections are asymmetric, being much faster downloads than uploads) or take practically forever to do the first full backup.  And they have either a monthly or yearly subscription.  If your internet connection has a fast upstream connection (10Mbs or better) and no data cap (highly unlikely) then we can talk about solutions like CrashPlan.)

Here’s the optimal plan:
  • Requires three external hard drives that are all more than twice the capacity of your computer.  (More capacity is better.)
  • One drive (probably your current one) is always connected when you are at your desk and is used for ongoing Time Machine backups.
  • Two drives that are rotated between a secured (and preferably fire-proof) storage container at your office location and an offsite storage location like a safety deposit box or something where no local disasters (flood, fire, tornado, earthquake, civil unrest) could destroy both your office and the offsite location.
  • For the full backups, you don’t use Time Machine; instead:
    • Connect the backup drive and create a folder at the top level that will contain the backup.  I usually call it something like “141016 JB’s MBPr Full b/u” so I can easily tell when (10/16/14) and what (my MacBook Pro retina).
    • Close all your applications.
    • Find your computer’s hard drive (usually called “Macintosh HD”) and then drag that inside the folder you created above.  You may have to enter your administrator username and password.
    • If that fails (due to permissions), you can just click on the Users folder and drag your user home directory to the folder you created.  It will likely be something like johndoe.  If you do that, you will get all of your data, but will not get your applications and system-level preferences.  That’s mostly OK, since you can likely reinstall the applications from the App store or the original media.
    • I like to do this process at bed time, after I am sure it’s working; it can take a few hours.
  • Once you make your first full backup, take it to your remote site.
  • You make and rotate your two full backups at a frequency where you could live over the loss of all of your activity since the last remote backup was made.  Usually a quarterly rotation is adequate.
  • When it’s time to do a new backup rotation, you backup to a new folder on the rotation drive you have at your office (delete the oldest folder on the drive if you don’t have enough free space) and then take it to the offsite location, swap it with the older rotation drive, and bring the older one back to the office.  You can do a full backup onto that drive when you get it back to the office if you want.
  • Never NEVER bring the offsite drive to the office and do the swap there.  That compromises the value of always having a remote backup.

Example screen shot:

Screen Shot 2014-10-16 at 2.04.52 PM

Here’s the mostly optimal plan:  (I’ve highlighted the differences in red.)
  • Requires two external hard drives that are all more than twice the capacity of your computer.  (More capacity is better.)
  • One drive (probably your current one) is always connected when you are at your desk and is used for ongoing Time Machine backups.
  • The other drive is stored at an offsite storage location like a safety deposit box or something where no local disasters (flood, fire, tornado, earthquake, civil unrest) could destroy both your office and the offsite location.
  • For the full backups, you don’t use Time Machine; instead:
    • Connect the backup drive and create a folder at the top level that will contain the backup.  I usually call it something like “141016 JB’s MBPr Full b/u” so I can easily tell when (10/16/14) and what (my MacBook Pro retina).
    • Close all your applications.
    • Find your computer’s hard drive (usually called “Macintosh HD”) and then drag that inside the folder you created above.  You may have to enter your administrator username and password.
    • If that fails (due to permissions), you can just click on the Users folder and drag your user home directory to the folder you created.  It will likely be something like johndoe.  If you do that, you will get all of your data, but will not get your applications and system-level preferences.  That’s mostly OK, since you can likely reinstall the applications from the App store or the original media.
    • I like to do this process at bed time, after I am sure it’s working; it can take a few hours.
  • Once you make your first full backup, take it to your remote site.
  • You make a backup at a frequency where you could live over the loss of all of your activity since the last remote backup was made.  Usually a quarterly rotation is adequate.
  • When it’s time to do a new backup, you retrieve your backup drive from the remote location and backup to a new folder on the drive (delete the oldest folder on the drive if you don’t have enough free space) and then take it back to the offsite location.
  • Note that while you have your backup drive at your office, your data is at risk.

One more important note:  In either case, you should keep your Time Machine backup going on the first, always-connected drive, and also keep the older backup folders on the full backup drive(s) until you have to delete them (thus the suggestion of more capacity than just 2x the Mac’s HD size).  The reason is that one important aspect of backup plans is how they protect you (or don’t) against corrupted / accidentally modified files.  You always want to keep old versions of files around since a multiply-redundant fail-safe backup of a corrupted file is still worthless.

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