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I have an Novell OES SP3 server (kernel = 2.6.5-7.244-smp) running on a SMP Dell PowerEdge 2550. The install seemed to go fine and the system boots up fine, however it appears that Linux isn't using all of
it's 1 gig of available physical RAM.
...You'll notice the "used" column only shows its using 313 RAM. Normally the "used" amount should be much closer to "total" as Linux tries to useall of its available memory at all times.
I ran memtest on the box for 2 days and it didn't detect any physical memory errors.
Any idea what could be stopping Linux from using the other ~700 megs of
RAM?
How long did you let it go before you checked it? Since it's using the free RAM as buffer/cache, it takes a while to use it all. The more programs you run and more times data is accessed, the more of the RAM it will use.
How long did you let it go before you checked it? Since it's using the free RAM as buffer/cache, it takes a while to use it all. The more programs you run and more times data is accessed, the more of the RAM it will use.
it will sit there for days only using between 200-350 RAM.
Distribution: Ubuntu Feisty Fawn, Fedora 7, Windows XP
Posts: 91
Rep:
Hey,
Linux has much better memory management than Windows. As soon as you boot up, before you use any programs, you're already using virtual memory with Windows. Not the case with Linux.
Check the /proc/meminfo file. If it is not reporting all your memory in total memory, make sure your kernel is compiled with High Memory support, set at at least 4Gigs.
Edit: Oh, I see that you already have memory reporting correctly. I'll have to agree, what you are seeing is just the great memory management of linux.
Linux has much better memory management than Windows. As soon as you boot up, before you use any programs, you're already using virtual memory with Windows. Not the case with Linux.
Regards,
Brandon
I understand that, however, run "free -m" on your system. the "used" will always be close to "total" amount because of the way the kernel handles memory.
Check the /proc/meminfo file. If it is not reporting all your memory in total memory, make sure your kernel is compiled with High Memory support, set at at least 4Gigs.
Edit: Oh, I see that you already have memory reporting correctly. I'll have to agree, what you are seeing is just the great memory management of linux.
The server preforms like it only has 200 megs of RAM. The "used" should always be close to "total" when typing "free -m" or have I always thought this and am crazy?
If you have nothing substantial running, why would it be using memory ???.
Normally you might expect a server would be using more cache than that - what does this return
Distribution: Ubuntu Feisty Fawn, Fedora 7, Windows XP
Posts: 91
Rep:
I think you're misunderstanding the command. The command is 'free -m', it displays your current memory usage. That's why 313 is under 'used'. Meaning, you're only using 313MB of your total RAM. Which is 1GB. Try running the command 'top'. This will tell you what each program is using in RAM. It's possible it could be 'tops', but most likely is 'top'. This is kind of like task manager for Windows.
If you have nothing substantial running, why would it be using memory ???.
Normally you might expect a server would be using more cache than that - what does this return
Code:
cat /proc/sys/vm/swappiness
Because Linux always uses as much memory as possible. It's a bit misleading when "free -m" shows that Linux is using too much memory.
Type "free -m" on an idle box and see what you get.
<--SNIP-->
To see how much memory you are currently using, run free -m. It will provide output like:
total used free shared buffers cached
Mem: 90 85 4 0 3 34
-/+ buffers/cache: 46 43
Swap: 9 0 9
The top row 'used' (85) value will almost always nearly match the top row mem value (90). Since Linux likes to use any spare memory to cache disk blocks (34).
The key figure to look at is the buffers/cache row used value (46). This is how much space your applications are currently using. For best performance, this number should be less than your total (90) memory. To prevent out of memory errors, it needs to be less than the total memory (90) and swap space (9).
I think you're misunderstanding the command. The command is 'free -m', it displays your current memory usage. That's why 313 is under 'used'. Meaning, you're only using 313MB of your total RAM. Which is 1GB. Try running the command 'top'. This will tell you what each program is using in RAM. It's possible it could be 'tops', but most likely is 'top'. This is kind of like task manager for Windows.
Regards,
Brandon
I don't think you understand how Linux handles memory, unless I'm crazy. What does "free -m" report on an idle machine for you?
It wouldn't be something silly like a kernel parameter that tells
the machine not to use more than that piddly amount? Check your
grub/lilo config. It certainly doesn't look right, and no, it's
not "Linux' great memory management at work".
If you have nothing substantial running, why would it be using memory ???.
Normally you might expect a server would be using more cache than that - what does this return
Distribution: Ubuntu Feisty Fawn, Fedora 7, Windows XP
Posts: 91
Rep:
I stand corrected, if that site is correct then that is weird. What does 'top' yield for you? Unfortunately, I can't do anything with my system as I am at work right now. We don't have Linux here.
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