I want to backup some files that I regularly work on on a separate medium. It is however not very convenient if I have to plug in usb drives or external harddisks all the time as I have to carry my laptop around a lot. Now I had the idea to use an SD card that I can just leave it plugged in my laptop. (The idea of this backup is just having the files saved on another medium than the harddrive.) Now I have following questions:
- Are SD cards suitable for this task?
- Does it damage the SD cards if they are repeatedly accessed for writing?
- How long can the data be stored on an SD card when it is not plugged in?
(All those points compared to an USB drive or an external harddrive.)
23 Answers
It is possible to do what you are describing, but an external drive or SSD is better suited because:
faster performance (SSD) Lifespan - see below
btw the data can be stored on the SSD "forever" - unlike CDs
Common criticism of flash-based storage like SDHC cards is the lack of "wear leveling." Wear leveling is a technique used in SSDs for prolonging the lifespan of flash memory. Flash memory is limited by the number of times data can be written and erased to the medium. Wear-leveling works around this limitation by arranging data so that erasures and re-writes are distributed evenly across the medium. In this way, no single sector of the flash prematurely fails due to a high number of write cycles.
But some dispute the limitation because: For example, the 16GB A-DATA SDHC card has an estimated endurance or lifetime of 1,000,000 write cycles. What does that mean is "real world" terms? You would have to constantly write, erase and re-write data non-stop for several years before you need to be concerned about failure.
3SD cards are meant to be written to. There is no reason not to use one.
Yes, flash medium will eventually wear out over time. However, modern flash media will last a very, very long time.
SD cards are non-volatile, therefore the data will survive, even without being plugged in for many years, if not decades.
As far as I have researched online about this, it really is a difficult issue to resolve. Hard disks do not wear out in terms of writes, but physical parts means almost always means they will fail faster. SD cards are more reliable in terms of survivability in rough handling, as dropping a hard drive is going to be a very rough day. Limited writes on SD cards and no wear leveling as @TomEus mentioned can be bad. Speeds can be better than HDDs if a high end SDHC storage technology is chosen. SD cards are very portable, HDD very clunky and need to be set on a table.
TLDR for me: If you buy a good SD card, and you know the write cycles are good, great, stick with that. If you know that the writes are no good, HDD for sure. Also, if the amount of data is a lot (over 1TB) use a hard drive at that point, SD card is far from value for money.
