RAM problem on 2007.0/1 machine - Mandriva

This is a discussion on RAM problem on 2007.0/1 machine - Mandriva ; Hi! I have 4 PC/Server with Mandriva 2007.0 or 2007.1 x86_64 installed in text mode only. All server has 1GB of RAM memory. I have 90% of memory busy and also a part of SWAP space. Why? Did you already ...

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Thread: RAM problem on 2007.0/1 machine

  1. RAM problem on 2007.0/1 machine

    Hi!
    I have 4 PC/Server with Mandriva 2007.0 or 2007.1 x86_64 installed in
    text mode only.
    All server has 1GB of RAM memory.
    I have 90% of memory busy and also a part of SWAP space.
    Why?
    Did you already happen this?
    Thanks.

    SysAdmin


  2. Re: RAM problem on 2007.0/1 machine

    On Tue, 16 Oct 2007 05:15:34 -0400, SysAdmin wrote:

    > I have 90% of memory busy and also a part of SWAP space.


    Linux, will swap out unused parts of applications, to increase
    the space available for caching/buffering directories, and large
    files.

    See http://rudd-o.com/archives/2007/10/0...w-to-fix-that/
    for why.

    Add
    sysctl -w vm.swappiness=1 # Stop applications from being swapped to disk
    sysctl -w vm.vfs_cache_pressure=50 # Don't shrink the inode cache
    to /etc/rc.d/rc.local, to change it.

    I've been testing this, since, I think, Bit Twister posted the link,
    and the perceived performance difference is quite noticable. May
    reduce true throughput, on a server only system though,

    Regards, Dave Hodgins

    --
    Change nomail.afraid.org to ody.ca to reply by email.
    (nomail.afraid.org has been set up specifically for
    use in usenet. Feel free to use it yourself.)

  3. Re: RAM problem on 2007.0/1 machine

    On Tue, 16 Oct 2007 09:15:34 +0000, SysAdmin wrote:

    > I have 4 PC/Server with Mandriva 2007.0 or 2007.1 x86_64 installed in
    > text mode only.


    Lucky you.

    > All server has 1GB of RAM memory.


    OK.

    > I have 90% of memory busy and also a part of SWAP space.


    That's normal.

    > Why?


    Because that's normal.

    > Did you already happen this?


    All the time.

    You need to ask yourself what is bothering you. Did you buy the memory so
    it wouldn't be used?

  4. Re: RAM problem on 2007.0/1 machine

    [CUT]
    >
    > > I have 90% of memory busy and also a part of SWAP space.

    >
    > That's normal.
    >

    [CUT]

    Nooo, it isn't normal!
    Sorry but my english isn't very good!!
    If I check the tasks with TOP or PS commands, I don't see which
    process uses this very big quantity of memory.
    If I reboot my server the memory busy is about 20% of total phisical
    memory, after some hours It increase up to 90%.

    I tried to shut down all services but nothing change.
    It seems a mandriva's bug!!!
    What you think about this?

    Thanks a lot!

    SysAdmin


  5. Re: RAM problem on 2007.0/1 machine

    On Tue, 16 Oct 2007 08:15:26 -0700, SysAdmin wrote:

    > Nooo, it isn't normal!


    Yes it is.

    > Sorry but my english isn't very good!! If I check the tasks with TOP or PS
    > commands, I don't see which process uses this very big quantity of
    > memory. If I reboot my server the memory busy is about 20% of total
    > phisical memory, after some hours It increase up to 90%.


    Yes, that's normal.

    > I tried to shut down all services but nothing change. It seems a
    > mandriva's bug!!!


    It's not a bug.

    > What you think about this?


    I think that the kernel is doing a very fine job of using the available
    memory.

    Do you actually have a problem with systems slowing down and crashing, or
    is it just a windroid reflex that memory being used is a bad thing?

  6. Re: RAM problem on 2007.0/1 machine

    On Tue, 16 Oct 2007 08:15:26 -0700, SysAdmin wrote:
    > [CUT]
    >>
    >> > I have 90% of memory busy and also a part of SWAP space.

    >>
    >> That's normal.
    >>

    > [CUT]
    >
    > Nooo, it isn't normal!


    It is on my machine.
    uptime
    11:52:16 up 3 days, 12:28, 7 users, load average: 2.22, 1.05, 0.39

    $ See
    $ free -m
    total used free shared buffers cached
    Mem: 947 920 26 0 25 617
    -/+ buffers/cache: 278 668
    Swap: 1200 0 1199

    Only on a new boot will you see free memory.
    Here, I just booted another machine and show

    $ free -m
    total used free shared buffers cached
    Mem: 725 97 628 0 5 46
    -/+ buffers/cache: 45 680
    Swap: 1019 0 1019

    Linux will release the used memory when it needs to, not after a
    program exits or quits.

  7. Re: RAM problem on 2007.0/1 machine

    On Tue, 16 Oct 2007 09:15:34 +0000, SysAdmin wrote:

    > Hi!
    > I have 4 PC/Server with Mandriva 2007.0 or 2007.1 x86_64 installed in
    > text mode only.
    > All server has 1GB of RAM memory.
    > I have 90% of memory busy and also a part of SWAP space.
    > Why?
    > Did you already happen this?
    > Thanks.
    >
    > SysAdmin


    How is it being used? It is normal for a bunch of memory to be used for
    'buffer' and 'cache'. This makes the system work more efficiently and is
    entirely normal. The reason you would not see it after a reboot is that it
    takes a little while for the buffers to fill up. When more RAM is needed
    by processed it can be reclaimed - that's what memory is for.

  8. Re: RAM problem on 2007.0/1 machine

    On Tue, 16 Oct 2007 11:15:26 -0400, SysAdmin wrote:

    >> > I have 90% of memory busy and also a part of SWAP space.

    >> That's normal.

    >
    > Nooo, it isn't normal!


    If you have constant swapping going on, that is not normal, unless you're
    running large applications.

    It is normal, to have some swap usage, once your been running for a while.

    Here's why ...

    Everytime you load a file/program into ram, it goes into the buffer, and
    maybe into the cache. That way, if to try to reload a file you've previously
    used, it's already in ram. Linux doesn't release any of that memory, until
    it needs more.

    When it need more, it looks at what is the least recently used ram.
    If it's a program, or an open file, it swaps that out, and used the
    space for the new file.

    You can change that using sysctl (see my earlier response).

    > If I check the tasks with TOP or PS commands, I don't see which
    > process uses this very big quantity of memory.


    Install htop, then you can sort it (press f6) by the column VIRT, to see
    which programs are using the most virtual memory.

    It's possible you have a program, with a memory leak, that really is
    using too much memory, but more likely, it's just a matter of learning,
    that linux uses all avaialble ram, all the time, to ensure the maximum
    system throughput.

    When you first start, it only uses as much as it needs.

    As you access more files, it'll use more and more, until there
    isn't much left. That's normal. This isn't windows If you load
    a large program/file, it'll release, or swap out, as much of the least
    recently accessed ram, as needed.

    Regards, Dave Hodgins

    --
    Change nomail.afraid.org to ody.ca to reply by email.
    (nomail.afraid.org has been set up specifically for
    use in usenet. Feel free to use it yourself.)

  9. Re: RAM problem on 2007.0/1 machine

    On 2007-10-16, Bit Twister wrote:
    >
    > Linux will release the used memory when it needs to, not after a
    > program exits or quits.


    When a program exits or quits, the memory the program was
    using for its process address space goes into the free list.
    Cached/buffered file space would not be freed.

    The following is the output from "free" taken right before,
    during, and right after a run of a Java program that uses a
    good quantity of memory.

    Right before the run:
    total used free shared buffers cached
    Mem: 1035456 989368 46088 0 118832 491908
    -/+ buffers/cache: 378628 656828
    Swap: 12583856 8 12583848

    During the run:
    total used free shared buffers cached
    Mem: 1035456 1018624 16832 0 118864 492136
    -/+ buffers/cache: 407624 627832
    Swap: 12583856 8 12583848

    Right after the run:
    total used free shared buffers cached
    Mem: 1035456 985044 50412 0 118764 487556
    -/+ buffers/cache: 378724 656732
    Swap: 12583856 8 12583848

    In this case, it looks like the run caused about 4MB of
    cached/buffered space to be used by the program and then
    freed when it existed, along with the RAM that had been used
    by the program's process address space.

    --
    Robert Riches
    spamtrap42@verizon.net
    (Yes, that is one of my email addresses.)

  10. Re: RAM problem on 2007.0/1 machine

    On 16 Ott, 23:00, "David W. Hodgins"
    wrote:
    > On Tue, 16 Oct 2007 11:15:26 -0400, SysAdmin wrote:


    [CUT]
    >
    > Everytime you load a file/program into ram, it goes into the buffer, and
    > maybe into the cache. That way, if to try to reload a file you've previously
    > used, it's already in ram. Linux doesn't release any of that memory, until
    > it needs more.
    >
    > When it need more, it looks at what is the least recently used ram.
    > If it's a program, or an open file, it swaps that out, and used the
    > space for the new file.
    >
    > You can change that using sysctl (see my earlier response).

    [CUT]
    > As you access more files, it'll use more and more, until there
    > isn't much left. That's normal. This isn't windows If you load
    > a large program/file, it'll release, or swap out, as much of the least
    > recently accessed ram, as needed.


    Hi!
    Thank you guys!
    I'm very happy for your many replies!
    I checked all my linux machines, also with other distro and I saw
    that what you say is correct.
    Now, I understood the normal behavior of linux 2.6 kernel.
    I'll try to use sysctl for my future needs!!
    Thanks a lot!

    SysAdmin



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