I am running a MacMini 2013 that has Mac OS X 10.9.3 installed and I want to use SD memory cards with Time Machine.

  1. Can I use the SD flash memory for a backup drive?
  2. What is the maximum size supported?
  3. Is the drive bootable for a recovery option?
  4. Would anyone recommend doing this?
  • Backup drive for Time Machine ?
    – StrawHara
    Commented Oct 23, 2014 at 5:40

3 Answers 3


While we don't know how large your SD card is, it is likely not big enough to support a backup. The information and link below provides details on how much space to plan for.

Answer by sameetandpotatoes just here

You probably want to check out this website for the most information, but here is the answer to your question, quoted from the website above:

1. How big a drive do I need for Time Machine?

A general "rule of thumb" is, to keep a reasonable "depth" of backups, Time Machine needs 2 to 4 times as much space as the data it's backing-up (not necessarily the entire size of your internal HD). Be sure to add the size of the data on any other drives/partitions you want to back up.

  • This doesn't really answer the user's questions as the information you copied and pasted is asking how big the Time Machine disk needs to be and if it can be used for other things. The user is asking specific questions in relation to using a flash memory drive as a backup medium.
    – tubedogg
    Commented Oct 23, 2014 at 6:14
  • The answer explain why Time Machine need memory, that sd-memory card can't do a entire Time Machine BackUp.
    – StrawHara
    Commented Oct 23, 2014 at 6:16
  • If that is the point you were trying to make, you included way too much information in my opinion. You also didn't explain to the user what you were trying to tell them or how it related to their question.
    – tubedogg
    Commented Oct 23, 2014 at 6:18
  • 1
    I'm just bringing some knowledge here. There are no answer, he can do a backup with a sd-card... But when you understand how many memory is needed, you can make your own conclusion. He didn't talk about his sd-card capacity, so i'm just telling that he need a lot of memory for a entire system backup.
    – StrawHara
    Commented Oct 23, 2014 at 6:26
  • @tubedogg Yeah you have last word, congratulations :)
    – StrawHara
    Commented Oct 23, 2014 at 17:59

There is a rule of thumb about 2-3x or 2-4x larger Time Machine partition than what is being backed up. So, depending upon your drive/data size, a suitable SDCard may be available.

However, I would worry as well about the speed of an SDCard doing Time Machine backup. Either the card reader/controller might be slow or the SDCard media might be slow.

So, it depends on how much data you want to back up, how big an SDCard you have, and how fast it is, as well as how fast your SDCard reader is.

Yes, it is possible to do recovery/boot from an SDCard.


I have separated my data onto different drives, using RAID for integrity and availability.

The core Yosemite with actual data in use does not exceed 60 GB of space. I use time machine with a cheap Lexar 64GB USB3 stick, connected to a USB2 port. Time machine runs without any noise - NAND is silent, no moves of the head, no spinning of the drive - or interruption.

The advantages: please note that USB Stick = SD card! 1. Medium is fast, silent, cheap & small 2. Multi purpose use as backup, repository for e. g. actual data while traveling, use to boot from foreign host, ... 3. Medium can be encrypted 4. Medium can be cloned for backup with Disk Utility or ccc within seconds to minutes, instead of CCC wobbling around the disk like there will be no tomorrow 5. Copy/clone can easily located in different places to make sure that data will available after original is being destroyed e. g. fire ...

regards tom

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