Home ยป Freeing up memory (RAM) on Ubuntu 8.04 Server [duplicate]

Freeing up memory (RAM) on Ubuntu 8.04 Server [duplicate]


You will notice that some of that is being consumed by “cache”.

This is just disk read/write being cached and you can basically assume its free because it will be dumped out as soon as something more important needs it.

It makes disk IO faster. ๐Ÿ™‚

I have presently 2G of disk cache on my box, makes things fast.

“free” is a poor memory analysis tool. I find “htop” a much more practical overall system management tool, which gives both a practical representation of memory use and a practical way to explore processes.

Like this, just prettier:

1  [|||||                                                                          5.0%]  Tasks: 156 total, 2 running
2  [|||                                                                            2.5%]     Load average: 0.29 0.30 0.31
Mem[|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||     1182/3967MB]     Uptime: 5 days, 16:25:36
Swp[||                                                                        37/2000MB]
Mem:3967M used:1182M buffers:0M cache:1952M

( if you’re wondering about the low uptime.. thats a laptop )

A lot of people might provide ways to negate caching to get stuff out of swap, but its more or less pointless. All you’ll end up doing is reducing performance, unless you have a program that is really memory intensive , but only runs intensively every few days so that when its not running intensively it gets swapped out, and when it does come on, you cant wait the ~.5 seconds it takes to swap it back into memory from disk.

I personally can’t think of any good program that matches these conditions. shrugs

The people whom wrote the kernel know more or less what they’re doing in this department, I’d trust their judgment unless you’re certain you know better.

as @Paul Betts said, Switching to lighttpd might help you save a bit. Depends on what you’re doing, there are always a few tradeoffs.

I’m using it on my vps. Only has 96M ram and 63M swap, and its only using 26M(no joke) and 35M respectively. And there’s a database running there as well. ( Postgres , but not really used )

Ignore the first line. The important numbers are on the “-/+ buffers/cache” line. Linux will clear cache and buffers to make way for processes.

My Debian server routinely shows between 2 and 10 megabytes of free space on the first line. The second line shows that I have 50 megabytes free. (With a total of 256 ram on the system)

Your numbers look fine. DO NOT clear your buffers/cache. You have more than enough free ram.

Now if you have no memory free for cache, your system will run slow. If you start using alot of swap you’re going to have problems serving webpages.

you need to change your swappiness (tells the kernel how much it should swap)

# sysctl -w vm.swappiness=0

setting it to 0 will tell the VM to keep as much data in memory as possible, but you need to go and read up on whats right for you, its hard to tell, but do some experimenting and see what you can come up with.

edit the vm.swappiness line in /etc/sysctl.conf to set it up at boot

in other words, you want to use the memory as much as possible and reduce the amount of swapping that occurs on disk

Related Solutions

Why not drop the “auto” keyword? [duplicate]

Your proposal would be rejected on the basis of backward compatibility alone. But let's say for the sake of argument that the standards committee like your idea. You don't take into account the numerous ways you can initialize a variable widget w; // (a) widget...

Recursive to iterative using a systematic method [closed]

So, to restate the question. We have a function f, in our case fac. def fac(n): if n==0: return 1 else: return n*fac(n-1) It is implemented recursively. We want to implement a function facOpt that does the same thing but iteratively. fac is written almost in...

How can I match values in one file to ranges from another?

if the data file sizes are not huge, there is a simpler way $ join input1 input2 | awk '$5<$4 && $3<$5 {print $2, $5-$3+1}' B100002 32 B100043 15 B123465 3 This Perl code seems to solve your problem It is a common idiom: to load the entire...

Javascript difference between “=” and “===” [duplicate]

You need to use == or === for equality checking. = is the assignment operator. You can read about assignment operators here on MDN. As a quick reference as you are learning JS: = assignment operator == equal to === equal value and equal type != not equal !==...

Compiler complains about misplaced else [closed]

Your compiler complains about an misplaced else because, well, there is an else without a preceding if: // ... for (j=1; j<n-i; j++) { if(a[j]<=a[j+1]) { // ... } // END OF IF } // END OF FOR else { continue; } // ... The else in your code does not follow...

Bootstrap – custom alerts with progress bar

/* !important are just used to overide the bootstrap css in the snippet */ .alertContainer { border-radius: 0 !important; border-width: 0 !important; padding: 0 !important; height: auto !important; position: absolute !important; bottom: 15px !important; left:...

How to Garbage Collect an external Javascript load?

Yes, s.onload = null is useful and will garbage collect! As of 2019, it is not possible to explicitly or programmatically trigger garbage collection in JavaScript. That means it collects when it wants. Although there is cases where setting to null may do a GC...

Math programming with python

At first, what you are looking for is the modulo operator and the function math.floor() Modulo from wikipedia: In computing, the modulo operation finds the remainder after division of one number by another (sometimes called modulus). for example: 12%12=0...

Android slide over letters to create a word [closed]

Here some advice you can use: First for each cell you can create an object that represents the state of that cell: class Cell { char mChar; int row,column; boolean isSelected; } then you can create a 2D array of your cells Cell[][] mTable = ... For views you...

Sum two integers in Java

You reused the x and y variable names (hence the variable x is already defined in method main error), and forgot to assign the ints read from the Scanner to the x and y variables. Besides, there's no need to create two Scanner objects. public static void...

Extend three classes that implements an interface in Java

Using this simplified implementation of the library, using method() instead of M(): interface IFC { void method(); } class A implements IFC { public void method() { System.out.println("method in A"); }; } As akuzminykh mentions in their comment You'd write a...

How to set the stream content in PHPExcel? [closed]

Okey, First thing first PHPExcel_Worksheet_MemoryDrawing() can't solve your problem if you insist to use stream content and pass that to your worksheet your PDF will not render your image. But you can use `PHPExcel_Worksheet_Drawing()' if you want to render...

How to remove all files from a directory?

Linux does not use extensions. It is up to the creator of the file to decide whether the name should have an extension. Linux looks at the first few bytes to figure out what kind of file it is dealing with. To remove all non-hidden files* in a directory use: rm...

Hacker used picture upload to get PHP code into my site

Client side validation The validation code you have provided is in JavaScript. That suggests it is code that you use to do the validation on the client. Rule number one of securing webapps is to never trust the client. The client is under the full control of...

First Time HTML5/CSS Site

Semantically, I would suggest using HTML5 elements more. For example, instead of... <div id="header"> <div id="logo"></div> </div> Use instead: (the ID can stay if you want it to) <header> <div id="logo"></div>...