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RAM percentage utilised in Linux

honzeland — Fri, 26 Dec 2008 04:08:00 GMT

--zz: http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1230261484567+28353475&threadId=1213960

Question:
We are planning to calculate the percentage of physical memory utilised as below:

System Page Size: 4Kbytes
Memory: 5343128K (1562428K) real, 13632356K (3504760K) virtual, 66088K free Page# 1/604

Now the formula goes as below:

(free memory / actual active real memory) * 100
(66088/1562428) * 100 = 4.22 %

Please let us know if its the correct formula .

Mainly we are interested in RAM percentage utilised

Reply 1:
Red Hat/Centos v 5 take spare ram and use it for a buffer cache.

100% memory allocation is pretty meaningless because allocation is almost always near 100%. The 2.6.x kernel permits rapid re-allocation of buffer to other purposes eliminating a performance penalty that you see on an OS like HP-UX

I'm not thrilled with your formula because it includes swap(virtual memory). If you start digging too deep into virtual memory, your system start paging processes from memory to disk and back again and slows down badly.

The formula is however essentially correct.

Reply 2:
Here, a quick example from the machine under my desk:
Mem: 3849216k total, 3648280k used, 200936k free, 210960k buffers
Swap: 4194296k total, 64k used, 4194232k free, 2986460k cached

If the value of 'Swap used' is up (i.e. hundreds of megabytes), then you've got an issue, but as you can see, it's only 64k here.
Your formula for how much memory is used is something along the lines of this:

(Used - (Buffers + Cached) / Total) * 100 = Used-by-programs%
(Free + Buffers + Cached / Total) * 100 = Free%

.. Roughly ..

honzeland 2008-12-26 12:08 发表评论

Vim使用技巧，长期更新中。。。

honzeland — Sat, 31 May 2008 09:22:00 GMT

1. 多行注释:
ctrl+v 进入列模式,向下或向上移动光标,把需要注释的行的开头标记起来,然后按大写的I,再插入注释符,比如#,再按esc,就会全部注释了.

honzeland 2008-05-31 17:22 发表评论

Ubuntu下Vim设置高亮

honzeland — Wed, 05 Mar 2008 03:55:00 GMT

1、sudo vim ~/.exrc
添加如下内容：
if ＆t_Co > 1
syntax enable
endif
2、如果不行，再sudo apt-get install vim

honzeland 2008-03-05 11:55 发表评论

Ubuntu下安装字体

honzeland — Wed, 05 Mar 2008 02:44:00 GMT

/usr/share/fonts/truetype/ 下面的某文件夹，例如yahei

cd /usr/share/fonts/truetype/yahei

sudo mkfontscale && sudo mkfontdir && sudo fc-cache -fv

honzeland 2008-03-05 10:44 发表评论

Ubuntu下安装vmvare

honzeland — Fri, 25 Jan 2008 09:41:00 GMT

参考： https://help.ubuntu.com/community/VMware/Workstation
下载tar包， rpm包安装没成功

sudo apt-get install ia32-libs这句好像没影响，因为测试机是amd－64

安装好后，登录guest OS后，再装vmware-tools，不要单独下载，之间vm-install vmware-tools就可以

honzeland 2008-01-25 17:41 发表评论

Ubuntu下配置匿名vsftp

honzeland — Thu, 17 Jan 2008 07:19:00 GMT

1. edit /etc/vsftpd.conf:
listen=YES
anonymous_enable=YES
local_enable=YES
write_enable=YES
local_umask=022
anon_upload_enable=YES
anon_mkdir_write_enable=YES
dirmessage_enable=YES
xferlog_enable=YES
connect_from_port_20=YES
chown_uploads=YES
chown_username=honzeland
ftpd_banner=Welcome to blah FTP service.
secure_chroot_dir=/var/run/vsftpd
pam_service_name=vsftpd
rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
anon_root=/home/ftp

2. Now we must make writable directory for anonymous user.
cd /home/ftp
sudo mkdir opendir
sudo chmod 777 opendir/

Note: 采用proftp作server，安装配置更容易

honzeland 2008-01-17 15:19 发表评论

Pidgin for ubuntu 6.10

honzeland — Sat, 02 Jun 2007 15:28:00 GMT

zz from http://swik.net/User:dnoble/Distributed+Collaboration+Blog/Pidgin+on+Ubuntu+6.10+(Edgy+Eft)/8ik1

1. Get the source bundle from the Pidgin download site

http://pidgin.im/pidgin/download/source/

2. Extract the contents

tar jxf pidgin-2.0.0.tar.bz2
cd pidgin-2.0.0

3. Install some prerequisites

sudo apt-get install \
    libglib1.2-dev \
    libglib2.0-dev \
    libgtk2.0-dev

sudo apt-get install \
    libnspr-dev \
    libnspr4 \
    libnspr4-0d \
    libnss3 \
    libnss3-0d \
    libnss-db \
    libnss-dev \
    libssl0.9.8 \
    libssl-dev \
    openssl \
    ssl-cert

(Thanks to the Ubuntu forums for tips on the SSL library packages)

4. Configure the build

Override defaults pointing to older versions of GLib and GTK, then generate the makefiles and other build configuration.

export GLIB_LFLAGS=-lglib-2.0
export GLIB_CFLAGS="-I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include"

export GTK_LFLAGS="-lgtk-x11-2.0 -lcairo -latk-1.0"
export GTK_CFLAGS="-I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include \
       -I/usr/include/cairo -I/usr/include/atk-1.0"

export pango_LIBS=-lpango-1.0
export pango_CFLAGS=-I/usr/include/pango-1.0

export CFLAGS="$GLIB_CFLAGS $GTK_CFLAGS $pango_CFLAGS"

./configure

Add a "--prefix=DIR" option to the configure command if you prefer to specify a custom installation directory.

****************************************************************************
./configure 出现错误

checking for LIBXML... no
no
configure: error:

You must have libxml2 >= 2.6.0 development headers installed to build.

于是安装
sudo apt-get install libxml2-dev
*****************************************************************************

5. Build the software

make

If that doesn't work, redirect the output of "make" to a file and search for the string "errors:" to see what went wrong:

make > OUTPUT 2>&1

6. Install the software

sudo make install

If you ran the configure script with a custom prefix option pointing to a directory that you can write to without root privileges, then you can run "make install" without the "sudo".

7. Done

So that's it. If you are upgrading from Gaim 1.5, all of your configuration will be copied from the .gaim directory to .purple in your home directory. Your log files will also be moved, but a symbolic link will point from the .gaim/logs directory to the .purple/logs directory.

honzeland 2007-06-02 23:28 发表评论

Ubuntu6.10安装日记

honzeland — Sat, 20 Jan 2007 10:51:00 GMT

1. 修改源并更新升级Ubuntu:参见 http://wiki.ubuntu.org.cn/%E5%BF%AB%E9%80%9F%E8%AE%BE%E7%BD%AE%E6%8C%87%E5%8D%97/EdgyEft
   注意：基本上可以按照该网页上的配置来实现，只是Lumaqq就不用装了

2. 以下软件安装可以先通过ubuntu自带的工具：应用程序 -> 添加/删除...来搜索关键字来查看是否存在

3. qq软件：eva      msn:使用gaim中自带的就可以了

4. 音乐：audacious or beep-media-player

5. 视频：参见 http://wiki.ubuntu.org.cn/EdgyGuide#head-a12a543ea800098877d88c7a8e2813dfb5253a55
   1) totem-xine: sudo apt-get install totem-xine w32codecs libxine-extracodecs
       注意：totem-xine在打开url时，需要在打开位置后，右击鼠标将选择的 X输入法改成默认，否则，点击打开位置后，totem-xine将会停止相应。
   2) vlc
   3) Mplayer
   4) realplayer

6. ftp client: KFTPgrabber or filezilla
   对于KFTPGrabber可以采用apt-get直接安装,安装后在 Setting -> Configure KFTPGrabber... -> 常规 -> Bookmarks 中的编码选择gb2312,然后在Bookmarks -> 编辑书签中每一站点Advanced中的服务器编码中选择gb2312
   对于filezilla：
在 Windows 上有個好用的 FTP client -- Filezilla，它就可以設定遠端 FTP Server 的編碼，而現在 Filezilla 也有 Linux 版本了，可以到它官方網站下載（http://filezilla-project.org/nightly.php），解開後（用 tar -jxvf）會有一個 filezilla3 的目錄，裡面分別有 bin, share 的目錄，你可以按照下面步驟來安裝：

   1) 把 filezilla3/bin/ 目錄下的檔案放在 /usr/local/bin 下（sudo mv filezilla3/bin/* /usr/local/bin/）。
   2) 把 filezilla3/share/ 目錄下的檔案放在 /usr/local/share/filezilla 目錄下（sudo mv filezilla3/share/filezilla /usr/local/share/）。
   3) 然後在 /usr/share/applications 下新增一個 filezilla.desktop 的檔案，內容如下：

          [Desktop Entry]
          Encoding=UTF-8
          Name=Filezilla 3
          Comment=Filezilla FTP Client
          Exec=filezilla
          Icon=/usr/local/share/filezilla/resources/filezilla.png
          Terminal=false
          Type=Application
          Categories=Application;Network;
這樣就可以在選單下啟動 Filezilla 了。
而設定遠端伺服器編碼的地方，必須要在站臺管理員裡設定才行，在站点管理 -> 字符集 -> 使用自定义字符集中选择gb2312

7. Qterm: 直接apt-get

8. chm 和 pdf浏览器采用添加/删除工具来实现

9. ubuntu默认没有装ssh服务，直接apt-get ssh就可以了

10. 更多参考http://hi.baidu.com/wmywind/blog/item/16cb6c6089a251de8cb10d62.html

honzeland 2007-01-20 18:51 发表评论