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by littlestymaar 745 days ago
> And you certainly don't want to system to swap in and out gigabytes of memory.

Why though?

Swapping 32GB of memory in and out of an NVMe SSD is much faster than swapping 1GB out of a spinning disk so I really don't get that argument.

3 comments

> Swapping 32GB of memory in and out of an NVMe SSD is much faster than swapping 1GB out of a spinning disk so I really don't get that argument.

This is true, but it still takes time. What kind of workload do you have where you swap out 32GB of RAM? If you are in this situation you almost certainly need to buy these additional 32GB of RAM.

What if I don't have no more free DIMM slots but I already have 1 TiB NVMe and I am fine with my workload being finished slightly (or even noticeably) slower as opposed to not being able to do at all?

As an example of such workload: a server, one of the many, that runs financial calculations from many web users. It's fine for it to become somewhat slower: we'll notice the performance degradation in the metrics and stop accepting new connections for a while. It is not fine for it to just die with OOM ― the users automatically will reconnect to other servers, leading to a sort of a thundering herd scenario.

> What if I don't have no more free DIMM slots but I already have 1 TiB NVMe and I am fine with my workload being finished slightly (or even noticeably) slower as opposed to not being able to do at all?

Then you obviously have a workload where having swap make sense (and you could even add swap on the fly in such a case). But that is not typical at all.

On a desktop/laptop, where most of the “used” RAM (browser tabs) isn't actually used at once.
Firefox (and I guess Chrome as well) throws aways memory of unused tabs.
You can't do that in all situations, since they could have important state.
Which is incredibly annoying and thankfully can be disabled.
But it is still more than an order of magnitude slower than RAM, and is harmful for the disk cells.

If you have enough money to provision NVMe and still swap multiple gigabytes, just get a 16GB RAM stick for $40.

>just get a 16GB RAM stick for $40

Laptops come with soldered RAM now where upgrades are not possible. And most people use laptops nowadays instead of desktops.

Buying another laptop to double your ram just because you hit the swap once in a blue moon is kinda wasteful.

If you are frequently swapping out 32GB, a laptop is not the right tool for the job.
Where did I say anything about swapping out entire 32GB? Why does everything need to be binary in this argument? As in you either swap 32GB or have swap disabled?

What if you from time to time you only swap a couple of GB? Isn't that better than having your system completely lock up and need rebooting?

> If you have enough money to provision NVMe and still swap multiple gigabytes, just get a 16GB RAM stick for $40.

Why should I pay $40 when I have way more than 16GB of free SSD storage on my computer already?!

Because:

> it is still more than an order of magnitude slower than RAM, and is harmful for the disk cells.

I mean, if that's not an issue for you, be my guest. But that's not the global optimum.

It's not slow enough for me to notice, and disk cells will likely outlive the rest of the computer anyway. Its not first generation SSD anymore.

Reusing hardware you already have clearly feels more optimal than buying new one because it makes things unnoticeably slower.

It's not that hard to max out system capacity on desktop boards. I'm using the maximum possible 128 GB RAM on my desktop.
NVMe is cheap in that I don’t really need everything I bought. But I use all of the RAM I have.
SSD write endurance scares me more than running out of memory.
Why? Have you actually looked at the numbers and did the math, or are you scared out of FUD and think the sky is falling every time write calls are made to the SSD?

I treat my 1TB SSD like a loaner and after doing the math, based on my write patterns in the last 2 years, the SSD should wear out in about ..checks notes.. 12 years. I'm a lot more likely to replace it 2-4 years though to upgrade to a bigger and faster model anyway.

Plus, all storage dies eventually, that's why backups are important. You paid for it, you might as well make the most use of it while it lasts instead of trying to "hypermile it" since you won't be leaving it as inheritance to your grandchildren.

You're correct but I'm not sure it's FUD though and more a legacy of the limitations of early SSDs, which were indeed quite vulnerable to wear.
But we don't live in legacy times we live in present times. So is it too much to expect people on a tech forum to be at least a bit up to date on the present tech instead of regurgitating fears 10 years out of date?

If you're wearing out your SSD life endurance in a few years, you have an issue.

I'm not disputing that (hence the “You're correct” at the beginning of my response), I'm just reacting to your mention of “FUD”.
Spend your 40$ on backups first, and not on more RAM