270 lines
4.5 KiB
HTML
270 lines
4.5 KiB
HTML
<HTML
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><HEAD
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>Tuning the buffermem</TITLE
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>Securing and Optimizing Linux: RedHat Edition -A Hands on Guide</TH
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>Chapter 31. Software -Server/File Sharing-Network</TD
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><A
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NAME="AEN22401"
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>31.9. Tuning the buffermem</A
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></H1
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><P
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> Another helpful tuning hint is to tell Linux the following: Use a minimum of 60 percent of memory for the buffer cache; only prune when the percentage of memory used for the buffer cache gets over 10 percent (this parameter is now unused);
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and allow the buffer cache to grow to 60 percent of all memory (this parameter is also unused now).
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</P
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><P
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> The default setup for the <TT
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CLASS="literal"
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>buffermem</TT
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> parameters under Red Hat Linux is:
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<TABLE
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WIDTH="100%"
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><TR
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><TD
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><PRE
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CLASS="programlisting"
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> "2 10 60"
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</PRE
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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> Under
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<SPAN
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><IMG
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SRC="./images/Version6.1.gif"
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ALT="Version 6.1"
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></IMG
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></SPAN
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>
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To change the values of buffermem, type the following command on your terminal:
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<TABLE
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><PRE
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CLASS="screen"
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> [root@deep ] /# echo "60 10 60" >/proc/sys/vm/buffermem
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</PRE
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></TD
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></TR
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></TABLE
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>
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You can put the above command in the <TT
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CLASS="filename"
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>/etc/rc.d/rc.local</TT
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> script file and avoid typing it again the next time your system reboots. You can find full details in the 2.2 kernel documentation in the file <TT
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CLASS="filename"
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>linux/Documentation/sysctl/vm.txt</TT
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> a
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nd also, you can check <A
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HREF="gen-optim.html"
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>General System Optimization</A
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>, for more information.
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</P
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><P
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> Under
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<SPAN
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CLASS="inlinemediaobject"
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><IMG
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SRC="./images/Version6.2.gif"
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ALT="Version 6.2"
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></IMG
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></SPAN
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>
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Edit the <TT
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CLASS="filename"
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>/etc/sysctl.conf</TT
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> file and add the following line:
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<TABLE
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BORDER="0"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><PRE
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CLASS="programlisting"
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> # Improve virtual memory performance
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vm.buffermem = 60 10 60
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</PRE
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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> You must restart your network for the change to take effect. The command to restart the network is the following:
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<TABLE
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BORDER="0"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><PRE
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CLASS="screen"
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> [root@deep ] /# /etc/rc.d/init.d/network <B
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CLASS="command"
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>restart</B
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>
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</PRE
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></TD
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></TR
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></TABLE
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>
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<TABLE
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><TR
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><TD
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><PRE
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CLASS="literallayout"
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><TT
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CLASS="computeroutput"
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> Setting network parameters [ OK ]
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Bringing up interface lo [ OK ]
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Bringing up interface eth0 [ OK ]
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Bringing up interface eth1 [ OK ]
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</TT
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></PRE
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></TD
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></TR
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></TABLE
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>
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Recall that the last two parameters, 10 and 60 are unused by the system so we don't need to change the default ones.
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</P
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