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Today when my daily backup prompted for my root password I suddenly got some bad feeling about it. I tried to understand what happens to my SSD disk if backup every day reads all my data and writes them into backup files especially on linux system.

I know it is unhealthy for SSD durability to do huge writes on daily basis. But my question is: can it drastically lower my disk's lifetime? I will appreciate any response that will help me decide whether to switch my backup to weekly basis.

I have Samsung 850 EVO SSD disk.

Jakub Hubert
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2 Answers2

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An SSD is based on flash memory. Data written to it lasts forever; however, it has a limited number of writes.
Thus, daily or even weekly backups have a dramatic effect on drive life.

It is preferable to put backups on a separate drive. While backups on the same drive(separate partition) can help you recover from system failures, it can not be used in the event of a drive failure.

ravery
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The 850 EVO has a write endurance of 150TBW IIRC. So let's assume you wrote 30GB a day:

150TB * 1024 = 153600GB
153600GB / 30 = 5120 cycles of 30GB
5120 cycles / 365 = 14 years

That was just an example with 30GB/day, but you can do the calculations yourself for how much data you write per day.

You may be interested in taking a look at my question of how to monitor TBW on Samusng SSDs over here: How can I monitor the TBW on my Samsung SSD?

Also, please keep in mind that hard drives have a limited number of write cycles as well. It's just a lot, lot more than SSDs :)

Bonus info:

Not all SSDs have a such a low write endurance. It used to be that SSD NAND was SLC (Single Level Cell) which meant that each cell stored only a single bit. But then, NAND companies discovered they could store 2 bits per cell (MLC, Multi Level Cell) by varying the voltage, like for instance 0-.25v == 00, .25v-.50v == 01, .50v-.75v == 10 and .75v-1.0v == 11. (Numbers are totally bogus, just trying to communicate the idea). Unsurprisingly, as the cells wear out they don't store the varying voltage as well, thus, MLC cells don't last as long as SLC cells. Now, they've figured out how to cram 3 bits per cell with TLC (Triple Level Cell) technology. As you can imagine, TLC drives such as your 850 EVO wear out even faster.

You'reAGitForNotUsingGit
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