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Author: Steve Litt
To: dng
New-Topics: Re: [DNG] ssd experience (was / and /usr)
Subject: Re: [DNG] running with separate / and /usr
tito via Dng said on Tue, 17 Jan 2023 08:14:58 +0100

>I always used WD RE 500 GB SATA HDs in my Nas boxes and they
>lasted years, some of them almost decades and are still happily
>spinning, just by scrubbing the raids daily, using smartd and good
>right-sized PSUs.

Let me ask this: Has anybody here had an SSD or NVMe go bad or become
read-only? I haven't. It just might be that the only reason spinning
rust seems to last longer is because it's been installed longer. It's
very possible that a reasonably cared for SSD/NVMe might last a decade

> One more point for HDs vs SSD/NVMe is that really
>important stuff even if the electronics fry or the house burns down
>could be recovered from the platters (Yes I know it costs a lot).

I vaccinate against such problems by backing up. And some backups go in
my bank's safety deposit box.

>> I think an SSD or NVMe stands an excellent chance of lasting 5 years
>> if you handle it like I do:
>> 1) Use no more than 15% of the SSD/NVMe.
>Like having a Ferrari car and never pushing the gas throttle more
>than 15% ?

Not really the same thing...

>Doesn't this increase the cost per GB almost 10 times?

Yes, but that's a very small part of the picture.

First, consider the following, on my computer:

/dev/sda: 12.7TB (contains /home and all my data)
/dev/sdb: 223GB (just a junk disk I threw in)
/dev/nvme0n1: 1.8TB (Contains /usr and the rest of the OS)

As you can see, the vast majority of my storage is spinning rust
(7200rpm). My NVMe contains only the OS, which is read-constantly,

So I don't view it as cost per GB, I view it as paying $100 to house
the operating system in an extremely fast configuration. The cost per
GB is more relevant to the spinning rust, which of course we all know
is much cheaper.

>> 2) Put /usr and /var, etc, on the SSD/NVMe, but not /home or other
>> data
>On /var there are lots of writes (same on /run) and rough processes
>can fill it up breaking the system so it is good practice to put it
>on a separate partition.

You're right, /var should not be on the NVMe, and in fact on my machine
/var is /dev/sda4. Everyone please ignore my suggestion to put /var on
your SSD/NVMe.

Once again, all of this is in the context of how suboptimal it is to
put /usr on / instead of having it be a mountpoint.


Steve Litt
Autumn 2022 featured book: Thriving in Tough Times