104 lines
4.6 KiB
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104 lines
4.6 KiB
HTML
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<TITLE>HOWTO: Multi Disk System Tuning: Appendix J: Example IV: Server with 4 Drives</TITLE>
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<LINK HREF="Multi-Disk-HOWTO-31.html" REL=next>
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<A HREF="Multi-Disk-HOWTO.html#toc30">Contents</A>
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<H2><A NAME="s30">30. Appendix J: Example IV: Server with 4 Drives</A></H2>
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<P>
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<!--
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disk!example!server, 4 drives
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-->
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This gives an example of using all techniques described earlier, short of
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RAID. It is admittedly rather complicated but offers in return high
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performance from modest hardware. Dimensioning are skipped but reasonable
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figures can be found in previous examples.
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<P>
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<BLOCKQUOTE><CODE>
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<PRE>
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Partition sda sdb sdc sdd
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---- ---- ---- ----
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1 root overview lib news
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2 swap swap swap swap
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3 home /usr /var/tmp /tmp
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4 spare root mail /var
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</PRE>
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</CODE></BLOCKQUOTE>
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<P>Setup is optimised with respect to track positioning but also for
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minimising drive seeks.
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<P>If you want DOS or Windows too you will have to use <CODE>sda1</CODE> for this
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and move the other partitions after that. It will be advantageous to
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use the swap partitions on <CODE>sdb2</CODE>, <CODE>sdc2</CODE> and <CODE>sdd2</CODE> for
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Windows swap, <CODE>TEMPDIR</CODE> and Windows temporary directory under these
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sessions. A number of other HOWTOs describe how you can make several
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operating systems coexist on your machine.
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<P>
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<P>For completeness a 4 drive example using several types of RAID is
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also given which is even more complex than the example above.
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<P>
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<BLOCKQUOTE><CODE>
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<PRE>
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Partition sda sdb sdc sdd
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---- ---- ---- ----
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1 boot overview news news
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2 overview swap swap swap
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3 swap lib lib lib
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4 lib overview /tmp /tmp
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5 /var/tmp /var/tmp mail /usr
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6 /home /usr /usr mail
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7 /usr /home /var
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8 / (root) spare root
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</PRE>
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</CODE></BLOCKQUOTE>
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<P>Here all duplicates are parts of a RAID 0 set with two exceptions,
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swap which is interleaved and home and mail which are implemented
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as RAID 1 for safety.
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<P>Note that boot and root are separated: only the boot file with the
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kernel has to reside within the 1023 cylinder limit. The rest of the
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root files can be anywhere and here they are placed on the slowest
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outermost partition. For simplicity and safety the root partition
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is not on a RAID system.
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<P>With such a complicated comes an equally complicated <CODE>fstab</CODE> file.
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The large number of partitions makes it important to do the <CODE>fsck</CODE>
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passes in the right order, otherwise the process can take perhaps
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ten times as long time to complete as the optimal solution.
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<P>
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<BLOCKQUOTE><CODE>
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<PRE>
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/dev/sda8 / ? ? 1 1 (a)
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/dev/sdb8 / ? noauto 1 2 (b)
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/dev/sda1 boot ? ? 1 2 (a)
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/dev/sdc7 /var ? ? 1 2 (c)
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/dev/md1 news ? ? 1 3 (c+d)
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/dev/md2 /var/tmp ? ? 1 3 (a+b)
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/dev/md3 mail ? ? 1 4 (c+d)
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/dev/md4 /home ? ? 1 4 (a+b)
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/dev/md5 /tmp ? ? 1 5 (c+d)
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/dev/md6 /usr ? ? 1 6 (a+b+c+d)
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/dev/md7 /lib ? ? 1 7 (a+b+c+d)
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</PRE>
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</CODE></BLOCKQUOTE>
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<P>The letters in the brackets indicate what drives will be active
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for each <CODE>fsck</CODE> entry and pass. These letters are <EM>not</EM> present
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in a real <CODE>fstab</CODE> file.
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All in all there are 7 passes.
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<P>
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<P>
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<HR>
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<A HREF="Multi-Disk-HOWTO-29.html">Previous</A>
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<A HREF="Multi-Disk-HOWTO.html#toc30">Contents</A>
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