Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD
On 09/12/2021 15:22, Alexander V. Makartsev wrote:
"Crucial MX500 250GB" is based on a NAND 3D TLC-3bit¹ ICs and rated only
100TBW.
That is a relatively small amount, if you compare it to the devices I
was talking about.
Now if you take 12% for 2 years of 100TBW drive, which may look like a
lot at a first glance and calculate the difference (300TBW / 100TBW = 3;
12 / 3 = 4), it won't look too off from what I've got in the SMART readings.
So now let's assume you will continue to use your SSDs like before, it
would take roughly 14 years more (12% / 2 years = 6% per year; 100 / 6 =
16) of continuous use to wear out.
That's way past their warranty period and by reaching that time they
already paid for themselves.
I monitor SMART very closely.
*SMART data:*
Device Model: CT250MX500SSD1
Power On: 18188 hours
Temperature: 38 °C
Reported Uncorrectable: 0
Offline Uncorrectable: 0
Reallocated NAND Blocks: 0
Unused Reserve NAND Blocks: 31
Life Used: 12%
Total Written: 12 TiB
Device Model: CT250MX500SSD1
Power On: 15601 hours
Temperature: 35 °C
Reported Uncorrectable: 0
Offline Uncorrectable: 0
Reallocated NAND Blocks: 0
Unused Reserve NAND Blocks: 28
Life Used: 12%
Total Written: 13 TiB
Since I use only part of the drive now, and rest is not partitioned,
drive sees this and recognizes as overprovisioning. Wear levelling
mechanisms can use this surface, drive doesn't need to remember states
of cells in this region. I might be wrong, but that's what happening I
think.
Since I did that, writes have stopped. Debian is running on these
drives, / partition, /home and /var are elsewhere. Nothing is happening
on these drives apart from apt updates sometimes. Usage didn't changed
With overprovisioning enabled now, I can easily run with drives in mint
condition for many years without worry.
--
With kindest regards, Piotr.
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