Siju George wrote: > srv1:~# free -m > total used free shared buffers cached > Mem: 3956 3538 418 0 0 181 > -/+ buffers/cache: 3356 600 > Swap: 9538 51 9486
That looks okay. You have 4G of ram and a good amount of swap configured. But even with 4G of ram you have used some swap space. > Vmstat 5 output is here > http://pastie.org/1240013 That definitely shows swapping. > cat /proc/meminfo' taken 3 times is here > http://pastie.org/1240016 Unfortunately I don't have time to analyze that information. Sorry. > Am I running short on RAM? I think so yes. Or rather you are needing more than you have available. You could add more ram. Or you could reduce your need for memory. Look at what processes are running on your machine and consuming memory. 4G of ram is quite a bit. If you are consuming that much and still needing more then I expect to see some large processes there that are leaking memory. Find those processes and take action. My favorite tool for doing this is 'htop'. $ sudo apt-get install htop Then run it and look at the "Mem" bar in the upper left. This is a curses bar graph display of memory use. Type in 'h' to get a help script explaining the colors. Green shows memory used by userland programs. Those are just normal programs. (Usually Firefox. :-) Blue and Yellow show memory used in buffer cache. Memory used in buffer cache is good memory that is working for you. The blank area is free memory. If your memory is display half green (userland program memory) and half blue/yellow (buffers / filesystem buffer cache) then I would consider that healthy enough. That would show plenty of space for everything. If you have just rebooted then I would expect to see a very little memory used and a lot of blank space showing free memory that is not yet doing anything. If the display shows 99% green (userland program memory) consuming almost all of your resources then that isn't healthy. That leaves almost no memory to be used for filesystem buffer cache. This means that instead of being able to work from ram that every filesystem access will need to read the hard disk and wait for the response. That is much slower than being able to read the file from ram when it is stored in filesystem buffer cache. I expect that your system when it gets into this problem state would show 99% green showing all memory consumed by userland processes and nothing left for buffer cache. And also that all previously used buffer cache had to be written to disk in order to be freed up. That also causes a pause while the disk is being written. That single line of display is extremely useful to me in understanding how memory is being used in a system and whether the system is operating in a healthy state or not. A note about free memory. Free memory is memory that is not working for you. Some people have a misconception that they should have a large amount of free memory. But why? The Linux kernel is going to try to put all memory to work for you. It will dynamically assign free memory to buffer cache or to program space or to its own purposes. If it needs to reclaim some of that cache then it will dynamically do so. Therefore you don't need to have a large amount of free memory. Memory from userland programs that exit will have all of their memory freed and that will become free memory. Over time that memory will be used by buffer cache or by new programs that are started. Then 'htop' can help you find processes that are consuming memory. The default is to sort the display by percent CPU usage. But you can change that to display sorted by resident set size. Press F6 and then use the cursor keys to change the sort-by setting to RES and then Enter. That will then display the largest memory consuming programs that are in memory at this time up top. Those are programs that are consuming the most memory and are actively using that memory. (If the process consumes a lot of memory but doesn't use it then it can be paged out to disk. It might consume very little resident memory in that case and probably isn't really a problem. Looking at the VIRTual process size is also useful.) Look for processes that are consuming all of your memory. Good luck! Bob
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