:: Re: [DNG] running with separate / a…
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Author: Antony Stone
To: dng
Subject: Re: [DNG] running with separate / and /usr
On Tuesday 17 January 2023 at 08:14:58, tito via Dng wrote:

> On Mon, 16 Jan 2023 19:10:35 -0500 Steve Litt wrote:
> > 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.

I agree that /var should not be on media which will wear out with frequent
writes. /usr is perfectly safe in my opinion (as someone pointed out,
possibly in this thread, /usr used to be NFS mounted read-only across several
machines for conservation of storage capacity), but /home is in my opinion
perfectly fine on SSD. As for "other data", I'd say it depends on what this
data is before you decide where to store it.

In my experience, /home is far less frequently written to than /var.

If you download and store email locally, then wherever *that* goes might be a
good source of churning data, but otherwise I regard /home as being pretty
slow-moving. Your mileage may of course vary, depending at the very least on
how far you drive in single journeys, what speed you get up to, how much your
speed varies, and how big you think a gallon is.

On my current (chimaera) systems, /run is a tmpfs, and as far as I'm aware
that means it's not even on physical media at all, therefore wear and tear on
/run isn't a question.

I categorise data into four groups:

1. Stuff which changes rapidly/frequently and needs fast access

2. Stuff which changes rapidly/frequently but does not need fast access

3. Stuff which doesn't change much and needs fast access

4. Stuff which doesn't change much and doesn't need fast access


1. Locally-stored email, typical databases

2. Log files

3. Operating system, application binaries and libraries

4. All the stuff you've had for years and probably forgotten exists

I put (1) on consumer-quality SSD and accept that it may wear out soon, so I
go for the best price per byte and expect to replace it often

I put (2) on local HDD and use Raid where the machine supports multiple drives

I put (3) on high-performance SSD and expect it to last longer than (1)

I put (4) on network storage, which is multi-Terabyte Raid spinning rust

As for backups, I simply use three editions of (4) in three physical


Software development can be quick, high quality, or low cost.

The customer gets to pick any two out of three.

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