USB Flash Drive For Long-Term Storage Of Data

Question

Is it a good idea to store the archives on a USB Flash Drive for at least 5 years? Will data be removed with the passage of time?

Use Case:-

1. I'll keep adding data in the USB with the passage of time.
2. As the USB drive will be full I'll put it in archives.
3. In the future I'll just copy or view the data on the USB drive.

Will my data be safe for next 5 years? If no then what's the maximum timespan of lossless data storage.

Solution

I have USB flash drives that are 5 years old that still work.

I have old 32MB and 64MB micro-SD cards that still work. I also have some that do not. A very old 128MB SmartMedia card (likely purchased around the year 2000 or so) I have also still works.

I will update this if I can find a source (or someone else can comment) but the memory cells in NAND are pretty much like a battery, and will lose their "charge" over time. So no NAND-based flash memory is going to last forever - not sure if the "shelf-life" is something like 10 years or 100 years.

EDIT: An article I cited while answering this question says typical times are 100 years, but I think this is for SLC flash. As stated in my other question I think it'd be less for MLC and TLC types of flash, which since it's cheaper is more likely what your flash drive has.

A good wear leveling algorithm should be copying and rewriting very old blocks - of course there's no way to tell what the microcontrollers in flash drives actually do.

Any good backup strategy is going to take into account "media refresh." Ideally you'd be copying your old backups, if you still need them, to new media on a regular basis. This is a good idea no matter what the media type.

Comments

[Omar Tariq]

I don't believe USB Flash drive is discussed there :-/

[DanteTheEgregore]

the important thing to note is that there's no guarantee your flash drive will be working in five years. Something could happen, it could be damaged. No electronic medium should be relied upon for long-term storage.

[MonkeyZeus]

If these archives are important to you then no. Electronic media storage is not meant to be a long-term worry-free solution. I read an article about some library that put a bunch of historical recordings onto hard drives and left them in storage for several years. When they went to retrieve this data years later it was unrecoverable on several of the disks. I guess they also got rid of the original storage medium so they are SOL.

[Omar Tariq]

Helpful answer. Will like to hear more about recovery of data from old USBs from others.

[Artanis]

Unfortunatly "still works" is not reliable measurement. For example - I also have four USB flash drives ranging from 1GB (Kingston, manufactured in 2007) to 16GB (noname, 2014), all filled with not-so-important photos. From time to time (twice a year or so) I connect them and browse through photos just to see that each time at least few of the files in each drive have been partly corrupted (bottom part of photo pixelated or lost color or just unreadable file). Technicaly most of the data are still there, but they are being irreversibly damaged over time. USB flash is NOT longterm storage!!!

[gaborous]

@Artanis I second this simply because USB flash drives mixup the reading mechanism and the storage medium, so they suffer from the same problems as the hard drives. Optical discs should be the most future-proof long-storage mediums.