I am looking for SD cards for my Pi's that are going to be the most stable, as I will be doing a lot of read/write. What type of SD cards will be the most reliable and be able to sustain a high volume of read/write? I'm not necessarily looking for a brand name, but more the type (SDHC vs SDXC; what Class number; etc...) although if you have had success with a certain brand, that could be helpful as well (as I know not all brands all compatible/approved).

  • 6
    If you are doing a serious amount or read/write cycles then you may want to look at booting from a HDD, even a good SD card will be limited in the number of RW cycles it can safely do.
    – user8894
    Jun 17, 2014 at 19:08

3 Answers 3


I am not a big fan of SD cards. I have had several go bad on me. I have had success using a USB Flash drive instead. You still need an SD card for the boot partition, but you can write protected it and use the USB for your filesystem. Here is a tutorial and another one here.

Basicly you need to do the following:

  1. Back up your SD card and flash the image onto the USB Drive. You don’t need the boot partition on the USB drive, and you don’t need the root filesystem on the SD card.
  2. Edit the cmdline.txt on the SD card to read root=/dev/sda2

Search for a good brand, SDHC (SDXC aren't supported), and Class 10. You can see the read/write speed rate. The better read speed that I saw so far is around 45MB/s.

  • Speed is obviously a plus, but I am more concerned with it being able to handle the volume of read/write (as these Pi's will be up 24/7 and doing a fair amount of work). I had read the not all SD cards were designed to be used in the manner they are with the Pi's, and can become corrupt after an excessive amount of use. This is what I am trying to avoid. Am I being misled by that piece of information or are there cards better designed to be used at a high frequency?
    – Rob_IGS
    Jun 17, 2014 at 18:39
  • If your concern is number of read/write cycles, the major feature to search for is the the brand. The brand reflect quality of material and some brands has premium products with even better quality. Do not buy a cheap and generic SD card. Something else that you can do is partition your storage in many partitions and set as read-only some of them. I also have the practice to clone and replace a SD card once a year, just to decrease the chance data loss due to fatigue of storage. But be sure that a good SD card can handle your high usage for a long time. Jun 17, 2014 at 20:01

This answer is a personal case, not a technical review.

I have the same concern @Rob_IGS. My RPis are on 24/7. I don't like to suggest brands, but I use Kingston SDHC Class 10. After trying about four different others cards, this one seems better. I've been using for about half year, almost non stop. Addicionally, you can:

  1. Make a better partitioning of your disk and mark some partitions as read-only.
  2. Set a higher delay of write cycles. Its a kernel parameter.
  3. Reduce the level of logs.

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