Server RAM question?

[Nate204]

Hey everyone!

I just had a quick question.

I'm currently running an Ubuntu server 10.10 with the specs below.

I just picked up 4GB of ram to add to the existing two.

My questions is this:
How much RAM can I use with my server? I've talked with a few people about it, but most don't seem to know because I'm the "one friend they know" who works with and around servers. All they seem have info on is with Desktop environments and Windows.

I guess I'm just trying to get my ducks in a row.

It has two Dual Core Xeon processors on board as you'll see below. I figured they both could run a max of 4GB each~ tot total 8GB if needed. Then again, that's why I'm here. I wanted to ask you =D

Thanks in advance everyone!!
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Operating system Ubuntu Linux 10.10

Kernel and CPU Linux 2.6.35-25-generic-pae on i686

Processor information Intel(R) Xeon(TM) CPU 2.80GHz, 4 cores

Real memory 1.96 GB total, 792.32 MB used

Virtual memory 1.49 GB total, 7.34 MB used

Local disk space 129.59 GB total, 24.16 GB used

[volkswagner]

Most likely your hardware is not limited to 8 gigs on a dual CPU. You should never assume, and check with the MOBO manufacturer for RAM specs.

You may need Physical Address Extension, which I see is enabled in your kernel...pae i686... you should be good to go!

[insane_alien]

if you're going to be using that much RAM i'd suggestgoing for 64-bit unless your xeons are 32-bit.

64-bit handles RAM much better than pae

[cascade9]

Most likely your hardware is not limited to 8 gigs on a dual CPU. You should never assume, and check with the MOBO manufacturer for RAM specs.

Yeah, good advice.

if you're going to be using that much RAM i'd suggestgoing for 64-bit unless your xeons are 32-bit.

64-bit handles RAM much better than pae

+1.

BTW, all the dual-core xeons are 64bit capable AFAIK.

[Nate204]

Thank you everyone for your help and suggestions!

You right! I got the RAM in today, and Installed it.
It shows under WebMin, that I have 4.9GB of space (I could only get in 5, due to only having 6 slots. The 2GB I had are both 512Mb each....

I tried to install a 64bit on Ubuntu and it wouldn't go. I then tossed in my 32bit OS disc and it started right up.

I'm having more troubles now as well. I'm trying to run application with a java (a game server), and I can't allocate the new RAM?

I know this is a long shot of a question, but does anyone know why?
Here is the command line I toss in, and It spit out an error telling me the size requested is larger than the allowed limit.

I know of other server running this same exact code, but they're not stopped by this message.

Command:
java -Xmx4096M -Xms4096M -cp mysql-connector-java-bin.jar:craftbukkit-0.0.1-SNAPSHOT.jar org.bukkit.craftbukkit.Main nogui

Here is a snip-it of my server info with Webmin:

(Note, This is from before Updates and new RAM added)

Thanks everyone for your assistance!
I appreciate it!

[Nate204]

Yeah, good advice.



+1.

BTW, all the dual-core xeons are 64bit capable AFAIK.

Just figured out I'm running x86 Doh!

I really don't want to do a re-install of everything just to see if I can run 64 bit.

Do you have a source I could look over first?

[The Real Dave]

Just figured out I'm running x86 Doh!

I really don't want to do a re-install of everything just to see if I can run 64 bit.

Do you have a source I could look over first?

If you simply want to see if your machine can run 64 bit Ubuntu run,

sudo lshw > hardware.txt

Open up the hardware.txt file, scroll down to your the information on your cpu. It'll list all it's capabilities flags. You're looking for the x86-64 flag.

You can also pop in a 64bit Ubuntu Live CD and see if it boots. If your computer is not 64bit capable, it won't boot.

[hawkmage]

On a 32 bit OS any one process can only see a 4GB memory space without using funky memory mapping techniques that often lead to more issues than they solve. In this 4GB memory space there is a portion that is reserved for the Kernel, usually 1GB, and the rest for the process to use leaving your application with 3GB to play with.

This is way you are getting the command is not allowed to allocate 4GB of memory. Try it with 3072MB.

My rule of thumb for choosing between 32 vs 64 bit OS is is there will be any single process that requires more than about 2GB to 2.5GB of ram. Above 2.5GB I go for 64 bit under 2GB then 32 bit unless there are many processes that will require large memory allocations.

[Nate204]

If you simply want to see if your machine can run 64 bit Ubuntu run,

sudo lshw > hardware.txt

Open up the hardware.txt file, scroll down to your the information on your cpu. It'll list all it's capabilities flags. You're looking for the x86-64 flag.

You can also pop in a 64bit Ubuntu Live CD and see if it boots. If your computer is not 64bit capable, it won't boot.

I checked out the specs with the code you provided. It seems to me that the CPUs both have a width of 32bits...

I'm really bummed out about this, but I should have checked and double checked. I'm brand new to server hardware and how it works, although 32bit and 64bit are the norm when dealing with builds. I guess I figured all server tech would be running 64bit hardware, but my Server doesn't seem to make the cut.

I guess I'm stuck until I either get two new CPUs or there is some odd way to get the 32bit of Java to utilize more than 1.5GB of RAM...... I should have known. lol

Thanks again everyone. You all just taught me more here than I feel I've learned so far in my Windows Server 2008 class.

I appreciate it!

[Nate204]

P.S.

This is what it shows for both CPUs.


*-cpu:0
description: CPU
product: Intel(R) Xeon(TM) CPU 2.80GHz
vendor: Intel Corp.
physical id: 4
bus info: cpu@0
version: 15.2.9
slot: CPU 1
size: 2800MHz
capacity: 2800MHz
¿½n��nwidth: 32 bits
clock: 133MHz
capabilities: boot fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe pebs bts cid x$
configuration: id=1