Author: sbalneav
Date: Fri Aug 31 20:35:37 2007
New Revision: 4310
Modified:
trunk/edubuntu/handbook/C/server.xml
Log:
Finished splitting up the topics, added a section on nbd-swap
Modified: trunk/edubuntu/handbook/C/server.xml
==============================================================================
--- trunk/edubuntu/handbook/C/server.xml (original)
+++ trunk/edubuntu/handbook/C/server.xml Fri Aug 31 20:35:37 2007
@@ -1091,6 +1091,37 @@
<para>Used to build the resolv.conf file.</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term>
+ <command>SOUND</command>
+ </term>
+ <listitem>
+ <para>This parameter enables sound for the thin
client. The default is
+ <command>Y</command>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <command>LOCALDEV</command>
+ </term>
+ <listitem>
+ <para>This parameter enables local devices support,
like CD's and
+ USB sticks. Users plugging them in should see them
on the desktop,
+ after they've been added to the fuse group on the
server. You can do
+ this by going to:
+ <menuchoice>
+ <guimenu>System</guimenu>
+
<guisubmenu>Administration</guisubmenu>
+ <guimenuitem>Users and
Groups</guimenuitem>
+ </menuchoice>
+ selecting the user, clicking on "Properties", the
going into the
+ "User Privileges" tab, and making sure the "Allow
use of FUSE filesystems..."
+ box is checked. The default is:
+ <command>Y</command>.
+ </para>
+ </listitem>
+ </varlistentry>
</variablelist>
</sect2>
<sect2>
@@ -1576,7 +1607,7 @@
<para>You have a choice of running the X Font Server
(XFS) or
reading the fonts through the file system. XFS
has been pretty much
superceeded by the RENDER extention of Xorg, but
for special cases, you
- can specify it.
+ can specify it.
The 2 values for this option are
<command>Y</command> and
<command>N</command>. The default value is
@@ -1643,206 +1674,168 @@
</variablelist>
</sect2>
<sect2>
- <title>Move this stuff around to topic based help</title>
- <sect3>
- <title>Available lts.conf parameters</title>
- <sect4>
- <title>General parameters</title>
- <variablelist>
- <varlistentry>
- <term>
- <command>SOUND</command>
- </term>
- <listitem>
- <para>This parameter enables sound for the
thin client. The default
- is
- <command>Y</command>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>LOCALDEV</command>
- </term>
- <listitem>
- <para>This parameter enables local devices
support, like CD's and
- USB sticks. Users plugging them in should
see them on the desktop,
- after they've been added to the fuse
group. The default is
- <command>Y</command>.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>CONSOLE_KEYMAP</command>
- </term>
- <listitem>
- <para>Allows you to specify a valid console
keymap for TELNET_HOST
- sessions. Default is
- <command>en</command>.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </sect4>
- <sect4>
- <title>Keyboard parameters</title>
- <para>All of the keyboard support files are copied into the
- /opt/ltsp/i386 hierarchy, so configuring international
keyboard
- support is simply a matter of configuring X.org. There
are several
- configuration parameters for this.
- </para>
- <para>The values for the above parameters are from the
X.org
- documentation. Whatever is valid for X.org is valid
for these
- parameters.
- </para>
- <para>We would like to add documentation to show what
values are
- needed for each type of international keyboard. If you
work with
- this and can configure your international keyboards,
feedback to
- Edubuntu would be greatly appreciated.
- </para>
- <variablelist>
- <varlistentry>
- <term>
- <command>XKBLAYOUT</command>
- </term>
- <listitem>
- <para>Consult the X.org documentation for
valid settings.</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>XKBMODEL</command>
- </term>
- <listitem>
- <para>Consult the X.org documentation for
valid settings.</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>XKBVARIANT</command>
- </term>
- <listitem>
- <para>Consult the X.org documentation for
valid settings.</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>XKBRULES</command>
- </term>
- <listitem>
- <para>Consult the X.org documentation for
valid settings.</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>XKBOPTIONS</command>
- </term>
- <listitem>
- <para>Consult the X.org documentation for
valid settings.</para>
- </listitem>
- </varlistentry>
- </variablelist>
- </sect4>
- <sect4>
- <title>Printer configuration parameters</title>
- <para>A printer can be connected to a diskless thin
client. A
- serial, parallel, or USB printer can be configured via
the
- following entries in the
- <command>lts.conf</command> file:
- </para>
- <variablelist>
- <varlistentry>
- <term>
- <command>PRINTER_0_DEVICE</command>
- </term>
- <listitem>
- <para>The device name of the printer. Names
such as
- <command>/dev/lp0</command>,
- <command>/dev/ttyS0</command> or
- <command>/dev/usblp0</command> are allowed.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>PRINTER_0_TYPE</command>
- </term>
- <listitem>
- <para>The type of the printer. Valid choices
are '
- <command>P</command>' or for Parallel, '
- <command>S</command>' for Serial, and '
- <command>U</command>' for USB.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>PRINTER_0_PORT</command>
- </term>
- <listitem>
- <para>The TCP/IP Port number to use. By
default, it will use '
- <command>9100</command>'
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>PRINTER_0_SPEED</command>
- </term>
- <listitem>
- <para>If the printer is serial, this is the
setting that will
- select the baud rate. By default, '
- <command>9600</command>' will be used.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>PRINTER_0_FLOWCTRL</command>
- </term>
- <listitem>
- <para>For serial printers, the flow control
can be specified.
- Either '
- <command>S</command>' for Software
(XON/XOFF) flow control, or '
- <command>H</command>' for Hardware
(CTS/RTS) flow control. If
- neither is specified, '
- <command>S</command>' will be used.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>PRINTER_0_PARITY</command>
- </term>
- <listitem>
- <para>For serial printers, the Parity can be
specified. The choices
- are: '<command>E</command>'-Even,
- '<command>O</command>'-Odd or
- '<command>N</command>'-None. If not
specified,
- '<command>N</command>' will be used.
- </para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term>
- <command>PRINTER_0_DATABITS</command>
- </term>
- <listitem>
- <para>For serial printers, the number of data
bits can be
- specified. The choices are:
- '<command>5</command>',
- '<command>6</command>',
- '<command>7</command>' and
- '<command>8</command>'. If not specified,
- '<command>8</command>' will be used.
- </para>
- </listitem>
- </varlistentry>
- </variablelist>
- </sect4>
- </sect3>
+ <title>Printer configuration parameters</title>
+ <para>Sometimes, it's convenient to hang a printer off of a thin
+ client in a lab, so that the computer lab has access to local
+ printing resources. Fortunately, LTSP can accomodate printing
+ on the workstation.
+ </para>
+ <para>LTSP can connect up to 3 printers per workstation to the
network
+ via a small daemon called JetPipe. Both parallel, and USB
printers
+ are supported. JetPipe makes the printer
+ look like a standard HP Jet Direct printer interface. You can
then
+ create any cups printer on your server, and point it at the
printer
+ via a Jet Direct connection.
+ </para>
+ <para>In your <filename>dhcpd.conf</filename> file that controls
your
+ thin client IP assignments, you'll want to assign a static IP
+ for the terminal with the printers, to guarentee that it gets
+ the same IP address every time it boots. Otherwise, your
printing
+ won't work if the terminal leases a different IP address.
+ </para>
+ <variablelist>
+ <title>Printing related parameters</title>
+ <varlistentry>
+ <term>
+ <command>PRINTER_0_DEVICE</command>
+ </term>
+ <listitem>
+ <para>The device name of the printer. Names such as
+ <command>/dev/lp0</command>, or
+ <command>/dev/usblp0</command> are allowed.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <command>PRINTER_0_PORT</command>
+ </term>
+ <listitem>
+ <para>The TCP/IP Port number to use. By default, it
will use '
+ <command>9100</command>', for PRINTER_0_DEVICE,
'<command>9101</command>' for PRINTER_1_DEVICE, and
+ '<command>9102</command>' for PRINTER_2_DEVICE.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
</sect2>
+ <sect2>
+ <title>Keyboard parameters</title>
+ <para>All of the keyboard support files are copied into the
+ /opt/ltsp/i386 hierarchy, so configuring international keyboard
+ support is simply a matter of configuring X.org. There are
several
+ configuration parameters for this.
+ </para>
+ <para>The values for the above parameters are from the X.org
+ documentation. Whatever is valid for X.org is valid for these
+ parameters.
+ </para>
+ <para>We would like to add documentation to show what values are
+ needed for each type of international keyboard. If you work
with
+ this and can configure your international keyboards, feedback
to
+ Edubuntu would be greatly appreciated.
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term>
+ <command>CONSOLE_KEYMAP</command>
+ </term>
+ <listitem>
+ <para>Allows you to specify a valid console keymap for
TELNET_HOST
+ sessions. Default is
+ <command>en</command>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <command>XKBLAYOUT</command>
+ </term>
+ <listitem>
+ <para>Consult the X.org documentation for valid
settings.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <command>XKBMODEL</command>
+ </term>
+ <listitem>
+ <para>Consult the X.org documentation for valid
settings.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <command>XKBVARIANT</command>
+ </term>
+ <listitem>
+ <para>Consult the X.org documentation for valid
settings.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <command>XKBRULES</command>
+ </term>
+ <listitem>
+ <para>Consult the X.org documentation for valid
settings.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
+ <command>XKBOPTIONS</command>
+ </term>
+ <listitem>
+ <para>Consult the X.org documentation for valid
settings.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </sect2>
+ </sect1>
+ <!-- Network Swap -->
+ <sect1>
+ <title>Network Swap</title>
+ <subtitle>Helping thin clients with smaller amounts of ram</subtitle>
+ <para>Just like on a full fledged workstation, it helps to have swap
defined
+ for your thin client. "Swap" is an area of disk space set aside
to allow
+ you to transfer information out of ram, and temporarily store it
on a hard
+ drive until it's needed again. It makes the workstation look like
it has
+ more memory than it actually does. For instance, if your
workstation has
+ 64 Megabytes of ram, and you configure 64 Megabytes of swap, it's
theoretically
+ possible to load a 128 Megabyte program.
+ </para>
+ <para>I say, "theoretically", becuase in practice, you want to avoid
swapping
+ as much as possible. A hard drive is several orders of magnatude
slower
+ than ram, and, of course, on a thin client, you don't even have a
hard drive!
+ You have to first push the data through the network to the
server's hard drive,
+ thus making your swapping even slower. In practice, it's best to
make sure
+ you have enough ram in your thin client to handle all your average
memory
+ needs.
+ </para>
+ <para>However, sometimes that's not possible. Sometimes, you're
re-using old
+ hardware, or you've simply got a program that isn't normally used,
but does
+ consume a lot of ram on the thin client when it does.
Fortunately, LTSP
+ supports swapping over the network via NBD, or Network Block
Devices. We include
+ a small shell script called nbdswapd, which is started via inetd.
It handles
+ creating the swap file, and setting up the swapping, and removing
the swap file
+ when it's no longer needed, after the terminal shuts down.
+ </para>
+ <para>By default, swap files are 32 Megabytes in size. This was
chosen to give your
+ workstation a little extra ram, but not use up too much disk
space. If you get some
+ random odd behaviour, such as Firefox crashing when viewing web
pages with a lot
+ of large pictures, you may want to try increasing the size of the
swap files. You can
+ do so by creating a file in the directory <filename
class="directory">/etc/ltsp</filename>
+ on the Edubuntu server, called <filename>nbdswapd.conf</filename>.
It it, you can set the
+ SIZE variable to the number of Megabytes you wish the file to be
sized to. For instance,
+ to create 128 Megabyte files, you'll want:
+ <screen>
+SIZE=128
+ </screen>
+ in the <filename>nbdswapd.conf</filename> file.
+ </para>
+ <para>Please note that this is a global setting for all swap files.
If your server has 40 thin
+ clients, each using 128 Megs of memory, you'll need 128 * 40 =
5120, or a little over 5
+ Gigabytes of space in your <filename
class="directory">/tmp</filename> directory, where
+ the swapfiles are stored.
+ </para>
</sect1>
<!-- Thin Client Manager -->
<sect1 id="ltsp-tcm" status="draft">
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