The amount of memory in basic 1U servers and our shifting views of it

September 11, 2022

One of the things happening here is that we're in the process of rolling over our Ubuntu 18.04 servers on to our current generations of server hardware as we rebuild them as Ubuntu 22.04 based machines. This (and other local events) has caused us to take a look at what older servers we want to keep and what ones we want to get rid of, or at least exile to the depths of the back shelves. Surprisingly, one factor is their CPU performance, but another one is how much RAM they have, and this has set me thinking about the (slowly) shifting scales of how much memory basic 1U servers come with and how much is what we consider 'adequate'.

These days, going through Dell's configurator for R350s and R250s (the current generation of what we have), it seems hard to get something with less than 16 GB of RAM and impossible to get something with less than 8 GB. What we consider to be our current servers all came with 8 GB of RAM as our floor amount (I don't know if we could have gotten them with less, but I suspect not). However, our smallest older servers go as low as 2 GB of RAM, with some having 4 GB. According to DMI information, the smallest DIMMs we have in any Ubuntu server are 2 GB DIMMs, so based on that we couldn't have servers with less than 2 GB of RAM in general.

As a practical matter, I don't think we'd deploy any reused server with less than 4 GB of RAM, and we might take the effort to bring them up to 8 GB. We have very few machines with less than 8 GB now, and it's not just because of the hardware generation they're on. We've simply wound up in a situation where we default to thinking that 8 GB is the minimum amount of RAM that a server should have (and we add more if it seems called for). Of course this isn't absolutely necessary; we probably have plenty of servers that don't really need 8 GB, and I've never had problems on my virtual machines with 4 GB.

I'm not energetic enough to trawl our records to see how much RAM various generations of servers were bought with, but there certainly was a day when 1 GB or 2 GB was what they came in the door with. Some very quick exploration suggests that we were getting basic servers with 1 GB of RAM as far back as fifteen years ago, and ten years ago we seem to have been on the cusp of only being able to get new servers with a minimum of 2 GB of RAM. We probably had a while when servers came in the door with 4 GB, but for the past few years 8 GB has been the minimum.

I suspect that this shift in server RAM sizes is driven by a similar effect to the shift in hard drive sizes (both SSDs and HDDs), where manufacturers mostly hold the price constant and keep increasing the DIMM size. I do sort of wish that memory DIMM sizes had risen at the same rate that SSD sizes did; instead, they seem to have stagnated for a while, and certainly didn't rise aggressively. (This is one reason that the current generation and the past generation of my desktops have had the same 32 GB of RAM, although my current generation is getting a bit old by now and prices might have shifted lately.)

(It certainly would be nice for 32 GB or 64 GB or even 128 GB to be a standard, inexpensive memory size. But not so much, at least for us, although it is now much more reasonable to have 32 GB machines and we have a number of them.)

Comments on this page:

By Arnaud Gomes at 2022-09-12 03:20:38:

It looks like you are still running everything on bare metal, aren't you? Virtualization makes these amounts of RAM sound really small.

The servers we are currently shutting down have become too small to be economically viable at 16 to 32 GB. Totally different context of course, I work at a web hosting company.

   -- A

32GB of DDR4-3200 ECC RAM is $130 at Crucial. Now, your older servers may not support that, but I don't think the cost of 64GB or 128GB is material compared to the rest of the cost of a new server. Even at home, all my machines purchased in the last 3 years or so, other than my M1 Macs with their extortionate Apple RAM pricing, have 64GB of RAM, even the Windows/Linux laptops.

Instance configurations across AWS generations show the same trend: bigger minimum, same or slightly higher cost, and big promotion of "performance per dollar." We wish we could get the necessary performance for fewer dollars, instead.

This ended up being a big driver toward t3 for EC2 instances (as the major limiting factor, we made RDS bigger, sooner.) So those have 1-2 GB in practice. RAM is pretty expensive in the cloud.

By Miksa at 2022-09-14 10:51:08:

I'm pretty amazed how small servers you are considering. In my university we would only consider virtual servers up to around 8 CPU, 32 GB of RAM and few terabytes of storage. And we have some virtual servers that go beyond that, to around 12 CPU, 128 GB.

Written on 11 September 2022.
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