Real RAM Numbers

[KnightOwl]

How much ram are people using to host a 20(ish) user Direwolf20 (either version) servers without bad lag? Seems like an easy question but my Google searches aren't turning up anything.

And yes I know other things are important.. just need to know amount of RAM.

Thanks!

 

[TheDJParadox]

I'm using 16GB on Unleashed for about 30 people. If that helps.

 

[KnightOwl]

That does help. Have you ever used less ram? Do you think you could support more with 16 GB or is 30 the limit?

 

[TheDJParadox]

Yes, you could most probably support them with less. When having around 30 people, We only use just under 50% of the RAM we have.

 

[draeath]

My qualifications here: I was a NOC technician and sysadmin for several years at a hosting datacenter. I was good at it, but I left because sleeping 3 hours a day is not very good for your long-term health. Keep that in mind when you read the below

I run a server that handles around 5 people (FTB Unleashed, we've also used Mindcrack and Ultimate in the past). The primary bottleneck seems to be CPU usage on the server, and network latency between the server and the clients.

I have it set to start with 4gb of RAM and to grow to 6gb, and this seems to be far more than is necessary. (I have it though... unallocated RAM is wasted RAM!)

Watch your server with something like htop, start with a smaller minimum with a large maximum and just see what the server allocates during peak time. This gives you an idea of what you need. Set something respectably higher than that just to allow for unexpected peaks.

I think you'll find that RAM is not where your "lag" comes from. It is most likely the fact that Minecraft, in 2013, remains single-threaded and is not thread-safe. See TickThreading as this may help you, but keep in mind it is experimental and it is likely to eat your children, after corrupting your chunks.

Network latency is, of course, mostly determined by your ISP, the client's ISP(s), and the geographical distance between. Now, if your server is overtaxed (load average is high) then you will see some additional latency as the kernel has trouble keeping up, but if that's the case then worrying about your RAM settings is the least of your concerns.

 

[Eyamaz]

My qualifications here: I was a NOC technician and sysadmin for several years at a hosting datacenter. I was good at it, but I left because sleeping 3 hours a day is not very good for your long-term health. Keep that in mind when you read the below

I run a server that handles around 5 people (FTB Unleashed, we've also used Mindcrack and Ultimate in the past). The primary bottleneck seems to be CPU usage on the server, and network latency between the server and the clients.

I have it set to start with 4gb of RAM and to grow to 6gb, and this seems to be far more than is necessary. (I have it though... unallocated RAM is wasted RAM!)

Watch your server with something like htop, start with a smaller minimum with a large maximum and just see what the server allocates during peak time. This gives you an idea of what you need. Set something respectably higher than that just to allow for unexpected peaks.

I think you'll find that RAM is not where your "lag" comes from. It is most likely the fact that Minecraft, in 2013, remains single-threaded and is not thread-safe. See TickThreading as this may help you, but keep in mind it is experimental and it is likely to eat your children, after corrupting your chunks.

Network latency is, of course, mostly determined by your ISP, the client's ISP(s), and the geographical distance between. Now, if your server is overtaxed (load average is high) then you will see some additional latency as the kernel has trouble keeping up, but if that's the case then worrying about your RAM settings is the least of your concerns.

I like this guy!

You will be surprised at the number of people that will argue the opposite, though.

 

[Dingham]

Also in agreement with what draeath has said. The main issue is with CPU nowadays. I've been running modded servers for 12months now and it's CPU that i watch carefully.

 

[Henry Link]

I've also found that HD speed on the server can induce lag. The server I run privately is an HP desktop box 8GB Intel i7 running ubuntu for an OS. After experimenting a little I found that the lag was reduced by replacing the primary HDD with an SSD. Both the OS and minecraft (DW20 1.4.7) run fine from it. I still keep a regular HDD in the system but it is only used by CRON to run backups of the world data.

 

[cjm721]

I run most mod packs and have always found CPU to be the issue. I have 32GB of ram and have been watching loads and 1.5.2 packs seem much more memory efficient (assume alot less memory leaks) to the point with 20 people on unleashed it was using 700MB of ram.

Then for CPU wise if you are smart about how you build you can make very high output bases with an extremely small foot print, yet at the same time build incorrectly I don't care how good your server is it wont do anything.

 

[MrBrunty]

The rule I have always gone by is 1 person = 100mb of ram maximum. therefore 2GB of RAM is technically enough on a vanilla server. On FTB due to the amount of extra data, for example chunks don't just contain blocks in FTB there is extra data to consider, for example a chunk will contain additional info on energy, vis etc... Therefore it is best to add an extra GB of RAM or 2 afterwards to accomodate this.

In practice however this is different. 100MB assumes everyone is of a substantial distance away from one another, i.e. their loading areas do not intertwine. This NEVER happens. and 4 people living within 50 blocks of eachother will load only 200MB. You also have to accomodate for items such as chunk loaders. Best bet is to either ban them or limit their chunk loading radius in the config files.

In short you could probably run off of 2GB of RAM however I would strongly advise getting 4GB. You probably won't use all the RAM but as the saying goes. Its better to have and not need, than to need and not have. Not to mention that this gives you the opportunity to increase the amount of people playing on your server more freely.