4 ms·

For me there is only one factor that matters in backup. Not restore/backup speed, not price per byte, not fashion - only reliability. Does the backup medium wil

For me there is only one factor that matters in backup. Not restore/backup speed, not price per byte, not fashion - only reliability. Does the backup medium will perform without corruption when times come to read it? That's the only thing that matters. I had this problem - store and forget, long time, as in decades. Tried a lot of stuff and: Personal conclusion - offline backup sucks, regardless of medium. Tape, harddisks, zip drives - demagnetization of medium. CD, bluray - scratch and you're done. Thumb stick, SSD, non-volatile memory in general - needs a plug-in once in a while. So what I use is encrypted volumes and upload to cloud...and a dedicated SSD that I have on me at all times if I need offline access (which gets plugged in daily).

Erlich_Bachman 7y ago
How are you gonna scratch your optical discs? Do you move them around all the time? Also with something like Rar recovery records or or other redundancy measures, a scratch does not mean that you are "done", because the data can be recovered anyway (with storage size penalty, but setting aside 10% of storage for being able to recover from random scratches is well worth it).
- masklinn 7y ago
  > How are you gonna scratch your optical discs? IME the problem of optical discs is that unless they're molded (ROM) they degrade over time.
  - Erlich_Bachman 7y ago
    Not M-Disc which is rated to last for 1000 years and can be burned with consumer grade burner.
    - masklinn 7y ago
      That's just the company's claims. When the Laboratoire National de Métrologie et d’Essais performed an extreme conditions accelerated aging test (90°C and 85% RH) they found the M-Disc to be no better than most quality DVD+R (<250h), with MPO's Gold and Northern Star's DataTresorDisc reaching 250h (but not 500) and Syylex's GlassMasterDisc surviving almost unscathed to 1000h. Sadly it looks like Syylex is as dead as Millenniata, Inc (though it looks like Verbatim still sells m-discs).
      - Erlich_Bachman 7y ago
        To be objective you should have mentioned that US Department of Defence did a similar test and they did end up claiming that M-discs lasted for longer than regular discs. It looks like someone took over the production of M-Disc (wiki: "The debt holders subsequently started a new company, Yours.co, to sell M-DISCs and related services."), not sure about Syylex. Syylex seems like the perfect solution (making discs in glass, the material that is routinely used in chemical labs due to it's inertness), but the problem always was that it cannot be burned at home...
masklinn 7y ago
> For me there is only one factor that matters in backup. Not restore/backup speed, not price per byte, not fashion - only reliability. Does the backup medium will perform without corruption when times come to read it? That's the only thing that matters. Only if the other parameters are within certain bounds, otherwise your backup medium would be macro-scale physical engraving on a highly resistant substrate, at least some sort of stone, ideally a refractory or noble metal. Rhodium would probably be your ideal standard.
bmrp 7y ago
> Thumb stick, SSD, non-volatile memory in general - needs a plug-in once in a while. What do you mean by this? It is non-volatile after all.
- adrian_b 7y ago
  Any non-volatile memory is characterized by a "retention time" after which it may loose the information stored in it. The retention time depends on the storage conditions, especially on temperature & humidity. For ancient flash memories, with large cells and 1 bit per cell, the retention time can be of 10 years or even 20 years. After that the capacitor will discharge, because the insulation is not perfect. For modern flash memories, with much smaller cells and wit 3 or even 4 bits per cell, the electrical charge variation that will lead to wrong bits is much less, so the retention time can vary from a few years for a new SSD stored at low temperature to a few months for a used SSD stored at a higher temperature. At a high enough temperature (not impossible to reach, e.g. when forgotten in sun light), the retention time can be reduced to days. When a SSD is used, i.e. it is powered, the microcontroller inside it rewrites its cells from time to time to avoid losing data. If you store it without using it, after the guaranteed retention time you may lose data. Consumer SSDs and memory sticks are guaranteed for a retention time of 1 year, so you should not expect more than that.
  - bmrp 7y ago
    I did not know they had to maintain data that way, but I guess it makes sense. That is good to know! Thanks for the explanation! Now I know to never use an SSD as backup o.O

Erlich_Bachman 7y ago

How are you gonna scratch your optical discs? Do you move them around all the time? Also with something like Rar recovery records or or other redundancy measures, a scratch does not mean that you are "done", because the data can be recovered anyway (with storage size penalty, but setting aside 10% of storage for being able to recover from random scratches is well worth it).

masklinn 7y ago
> How are you gonna scratch your optical discs? IME the problem of optical discs is that unless they're molded (ROM) they degrade over time.
- Erlich_Bachman 7y ago
  Not M-Disc which is rated to last for 1000 years and can be burned with consumer grade burner.
  - masklinn 7y ago
    That's just the company's claims. When the Laboratoire National de Métrologie et d’Essais performed an extreme conditions accelerated aging test (90°C and 85% RH) they found the M-Disc to be no better than most quality DVD+R (<250h), with MPO's Gold and Northern Star's DataTresorDisc reaching 250h (but not 500) and Syylex's GlassMasterDisc surviving almost unscathed to 1000h. Sadly it looks like Syylex is as dead as Millenniata, Inc (though it looks like Verbatim still sells m-discs).
    - Erlich_Bachman 7y ago
      To be objective you should have mentioned that US Department of Defence did a similar test and they did end up claiming that M-discs lasted for longer than regular discs. It looks like someone took over the production of M-Disc (wiki: "The debt holders subsequently started a new company, Yours.co, to sell M-DISCs and related services."), not sure about Syylex. Syylex seems like the perfect solution (making discs in glass, the material that is routinely used in chemical labs due to it's inertness), but the problem always was that it cannot be burned at home...

masklinn 7y ago

> For me there is only one factor that matters in backup. Not restore/backup speed, not price per byte, not fashion - only reliability. Does the backup medium will perform without corruption when times come to read it? That's the only thing that matters. Only if the other parameters are within certain bounds, otherwise your backup medium would be macro-scale physical engraving on a highly resistant substrate, at least some sort of stone, ideally a refractory or noble metal. Rhodium would probably be your ideal standard.

bmrp 7y ago

> Thumb stick, SSD, non-volatile memory in general - needs a plug-in once in a while. What do you mean by this? It is non-volatile after all.

adrian_b 7y ago
Any non-volatile memory is characterized by a "retention time" after which it may loose the information stored in it. The retention time depends on the storage conditions, especially on temperature & humidity. For ancient flash memories, with large cells and 1 bit per cell, the retention time can be of 10 years or even 20 years. After that the capacitor will discharge, because the insulation is not perfect. For modern flash memories, with much smaller cells and wit 3 or even 4 bits per cell, the electrical charge variation that will lead to wrong bits is much less, so the retention time can vary from a few years for a new SSD stored at low temperature to a few months for a used SSD stored at a higher temperature. At a high enough temperature (not impossible to reach, e.g. when forgotten in sun light), the retention time can be reduced to days. When a SSD is used, i.e. it is powered, the microcontroller inside it rewrites its cells from time to time to avoid losing data. If you store it without using it, after the guaranteed retention time you may lose data. Consumer SSDs and memory sticks are guaranteed for a retention time of 1 year, so you should not expect more than that.
- bmrp 7y ago
  I did not know they had to maintain data that way, but I guess it makes sense. That is good to know! Thanks for the explanation! Now I know to never use an SSD as backup o.O