Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD
On 09.12.2021 15:22, piorunz wrote:
On
09/12/2021 00:14, Alexander V. Makartsev wrote:
I'd advise against doing extra
over-provisioning and making /swap on
slow HDD.
IMO it is a thing of the past, especially on a home\personal
computer.
Modern NAND technology and provisioning algorithms made SSDs
quite
resilient.
It is more likely that a controller IC will fail than a NAND ICs
will
wear off themselves during mild daily usage.
I disagree. I was quite surprised that my 2x Crucial MX500 250GB
3D
drives which I use in mdadm RAID1, saying that they are 12% used
in 2
years of use. That's because I created one big partition for
entire
drive and used it that way. Most of it was free anyway. They are
used as
/ in my server, mostly just idling, as all work is being done on
HDD
RAID (/home and /var is on HDDs too). Now, I trimmed down Ext4
partition
and mdadm RAID surface underneath it, and left free space at the
end of
the drive. Slow creep of life used has stopped and I am on 12% on
both
drives for few months now. Nothing else has changed, and life use
stopped.
Maybe Crucial drives are just more honest than other drives who
say 2%
use after 5 years of operation?
Usage will be different for everyone and in perfect scenario you
have to estimate how much data you would write to SSD daily, before
you purchase them.
Also, you have to keep in mind TBW ratings of devices you have and
NAND type they based on.
Published ratings should be a result of standardized testing
procedures which were developed by JEDEC.
This costs money and its the reason why some SSD manufacturers hide
ratings and/or NAND types of their products from specifications.
"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.
As you can see, as long as you buy drives with your workload in
mind, make backups (which you should do anyway) and monitor the
SMART, there is almost zero reasons to buy a SSD and not use it to
it's full potential.
The data will be spread out among NAND ICs² evenly by provisioning
algorithms anyway and IMO leaving extra unpartitioned space won't do
anything useful.
If I remember correctly, there was a time in early SSD days when
doing that was recommended, but I don't think this is still needed,
because modern SSDs became quite spacious and their controllers and
firmware evolved.
¹ Crucial\Micron is hiding the actual NAND type, like many others,
presenting marketing fluff instead, and I assume it is an older 3D
TLC 3-bit with low layer count and hopefully not QLC.
² Usually inside a cheap consumer-grade devices only two NAND ICs,
often even without DRAM buffer.
--
With kindest regards, Alexander.
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