+++ /dev/null
-<?xml version="1.0" encoding="UTF-8"?>
-<refentry id="fs_checkservers1">
- <refmeta>
- <refentrytitle>fs checkservers</refentrytitle>
- <manvolnum>1</manvolnum>
- </refmeta>
- <refnamediv>
- <refname>fs checkservers</refname>
- <refpurpose>Displays the status of server machines</refpurpose>
- </refnamediv>
- <refsect1>
- <title>Synopsis</title>
- <para><emphasis role="bold">fs checkservers</emphasis> [<emphasis role="bold">-cell</emphasis> <<emphasis>cell to check</emphasis>>] [<emphasis role="bold">-all</emphasis>] [<emphasis role="bold">-fast</emphasis>]
- [<emphasis role="bold">-interval</emphasis> <<emphasis>seconds between probes</emphasis>>] [<emphasis role="bold">-help</emphasis>]</para>
-
- <para><emphasis role="bold">fs checks</emphasis> [<emphasis role="bold">-c</emphasis> <<emphasis>cell to check</emphasis>>] [<emphasis role="bold">-a</emphasis>] [<emphasis role="bold">-f</emphasis>]
- [<emphasis role="bold">-i</emphasis> <<emphasis>seconds between probes</emphasis>>] [<emphasis role="bold">-h</emphasis>]</para>
-
- </refsect1>
- <refsect1>
- <title>Description</title>
- <para>The <emphasis role="bold">fs checkservers</emphasis> command reports whether certain AFS server machines
- are accessible from the local client machine. The machines belong to one
- of two classes, and the Cache Manager maintains a list of them in kernel
- memory:</para>
-
- <itemizedlist>
- <listitem>
- <para>The database server machines in every cell listed in the local
- <replaceable>/usr/vice/etc/CellServDB file</replaceable>, plus any machines added to the memory
- list by the <emphasis role="bold">fs newcell</emphasis> command since the last reboot.</para>
-
- </listitem>
- <listitem>
- <para>All file server machines the Cache Manager has recently contacted, and
- which it probably needs to contact again soon. In most cases, the Cache
- Manager holds a callback on a file or volume fetched from the machine.</para>
-
- </listitem>
- </itemizedlist>
- <para>If the Cache Manager is unable to contact the vlserver process on a
- database server machine or the <emphasis role="bold">fileserver</emphasis> process on a file server
- machine, it marks the machine as inaccessible. (Actually, if a file server
- machine is multihomed, the Cache Manager attempts to contact all of the
- machine's interfaces, and only marks the machine as down if the
- <emphasis role="bold">fileserver</emphasis> fails to reply via any of them.) The Cache Manager then
- periodically (by default, every three minutes) sends a probe to each
- marked machine, to see if it is still inaccessible. If a previously
- inaccessible machine responds, the Cache Manager marks it as accessible
- and no longer sends the periodic probes to it.</para>
-
- <para>The <emphasis role="bold">fs checkservers</emphasis> command updates the list of inaccessible machines
- by having the Cache Manager probe a specified set of them:</para>
-
- <itemizedlist>
- <listitem>
- <para>By default, only machines that are marked inaccessible and belong to the
- local cell (the cell listed in the local <replaceable>/usr/vice/etc/ThisCell</replaceable>
- file).</para>
-
- </listitem>
- <listitem>
- <para>If the <emphasis role="bold">-cell</emphasis> argument is included, only machines that are marked
- inaccessible and belong to the specified cell.</para>
-
- </listitem>
- <listitem>
- <para>If the <emphasis role="bold">-all</emphasis> flag is included, all machines marked inaccessible.</para>
-
- </listitem>
- </itemizedlist>
- <para>If the <emphasis role="bold">-fast</emphasis> flag is included, the Cache Manager does not probe any
- machines, but instead reports the results of the most recent previous
- probe.</para>
-
- <para>To set the interval between probes rather than produce a list of
- inaccessible machines, use the <emphasis role="bold">-interval</emphasis> argument. The non-default
- setting persists until the machine reboots; to preserve it across reboots,
- put the appropriate <emphasis role="bold">fs checkservers</emphasis> command in the machine's AFS
- initialization files.</para>
-
- </refsect1>
- <refsect1>
- <title>Cautions</title>
- <para>The command can take quite a while to complete, if a number of machines do
- not respond to the Cache Manager's probe. The Cache Manager probes
- machines sequentially and waits a standard timeout period before marking
- the machine as unresponsive, to allow for slow network communication. To
- make the command shell prompt return quickly, put the command in the
- background. It is harmless to interrupt the command by typing Ctrl-C or
- another interrupt signal.</para>
-
- <para>Note that the Cache Manager probes only server machines marked
- inaccessible in its memory list. A server machine's absence from the
- output does not necessarily mean that it is functioning, because it
- possibly is not included in the memory list at all (if, for example, the
- Cache Manager has not contacted it recently). For the same reason, the
- output is likely to vary on different client machines.</para>
-
- <para>Unlike most <emphasis role="bold">fs</emphasis> commands, the fs checkservers command does not refer to
- the AFSCELL environment variable.</para>
-
- </refsect1>
- <refsect1>
- <title>Options</title>
- <variablelist>
- <varlistentry>
- <term><emphasis role="bold">-cell</emphasis> <<emphasis>cell to check</emphasis>></term>
- <listitem>
- <para>Names each cell in which to probe server machines marked as
- inaccessible. Provide the fully qualified domain name, or a shortened form
- that disambiguates it from the other cells listed in the local
- <replaceable>/usr/vice/etc/CellServDB</replaceable> file. Combine this argument with the <emphasis role="bold">-fast</emphasis>
- flag if desired, but not with the <emphasis role="bold">-all</emphasis> flag. Omit both this argument
- and the <emphasis role="bold">-all</emphasis> flag to probe machines in the local cell only.</para>
-
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><emphasis role="bold">-all</emphasis></term>
- <listitem>
- <para>Probes all machines in the Cache Manager's memory list that are marked
- inaccessible. Combine this argument with the <emphasis role="bold">-fast</emphasis> flag if desired, but
- not with the <emphasis role="bold">-cell</emphasis> argument. Omit both this flag and the <emphasis role="bold">-cell</emphasis>
- argument to probe machines in the local cell only.</para>
-
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><emphasis role="bold">-fast</emphasis></term>
- <listitem>
- <para>Displays the Cache Manager's current list of machines that are
- inaccessible, rather than sending new probes. The output can as old as the
- current setting of the probe interval (by default three minutes, and
- maximum ten minutes).</para>
-
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><emphasis role="bold">-interval</emphasis> <<emphasis>seconds between probes</emphasis>></term>
- <listitem>
- <para>Sets or reports the number of seconds between the Cache Manager's probes
- to machines in the memory list that are marked inaccessible:</para>
-
- <itemizedlist>
- <listitem>
- <para>To set the interval, specify a value from the range between 1 and <computeroutput>600</computeroutput>
- (10 minutes); the default is <computeroutput>180</computeroutput> (three minutes). The issuer must be
- logged in as the local superuser <computeroutput>root</computeroutput>. The altered setting persists
- until again changed with this command, or until the machine reboots, at
- which time the setting returns to the default.</para>
-
- </listitem>
- <listitem>
- <para>Provide a value of <computeroutput>0</computeroutput> (zero) to display the current interval setting. No
- privilege is required. Do not combine this argument with any other.</para>
-
- </listitem>
- </itemizedlist>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><emphasis role="bold">-help</emphasis></term>
- <listitem>
- <para>Prints the online help for this command. All other valid options are
- ignored.</para>
-
- </listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
- <refsect1>
- <title>Output</title>
- <para>If there are no machines marked as inaccessible, or if all of them now
- respond to the Cache Manager's probe, the output is:</para>
-
-<programlisting>
- All servers are running.
-
-</programlisting>
- <para>Note that this message does not mean that all server machines in each
- relevant cell are running. The output indicates the status of only those
- machines that the Cache Manager probes.</para>
-
- <para>If a machine fails to respond to the probe within the timeout period, the
- output begins with the string</para>
-
-<programlisting>
- These servers unavailable due to network or server problems:
-
-</programlisting>
- <para>and lists the hostname of each machine on its own line. The Cache Manager
- stores machine records by Internet address, so the format of each hostname
- (uppercase or lowercase letters, or an Internet address in dotted decimal
- format) depends on how the local cell's name service translates it at the
- time the command is issued. If a server machine is multihomed, the output
- lists only one of its interfaces (usually, the currently most preferred
- one).</para>
-
- <para>If the <emphasis role="bold">-interval</emphasis> argument is provided with a value between <computeroutput>1</computeroutput> and
- <computeroutput>600</computeroutput>, there is no output. If the value is <computeroutput>0</computeroutput>, the output reports the
- probe interval as follows:</para>
-
-<programlisting>
- The current down server probe interval is &lt;interval&gt; secs
-
-</programlisting>
- </refsect1>
- <refsect1>
- <title>Examples</title>
- <para>The following command displays the Cache Manager's current list of
- unresponsive machines in the local cell, rather than probing them
- again. The output indicates that if there were any machines marked
- inaccessible, they all responded to the previous probe.</para>
-
-<programlisting>
- % fs checkservers -fast
- All servers are running.
-
-</programlisting>
- <para>The following example probes machines in the Cache Manager's memory list
- that belong to the <computeroutput>stateu.edu</computeroutput> cell:</para>
-
-<programlisting>
- % fs checkservers -cell stateu.edu
- All servers are running.
-
-</programlisting>
- <para>The following example probes all server machines in the Cache Manager's
- memory list. It reports that two machines did not respond to the probe.</para>
-
-<programlisting>
- % fs checkservers -all
- These servers unavailable due to network or server problems:
- fs1.abc.com SV3.STATE.EDU.
-
-</programlisting>
- </refsect1>
- <refsect1>
- <title>Privilege Required</title>
- <para>To set the probe interval, the issuer must be logged in as the local
- superuser <computeroutput>root</computeroutput>. Otherwise, no privilege is required.</para>
-
- </refsect1>
- <refsect1>
- <title>See Also</title>
- <para><link linkend="CellServDB5">CellServDB(5)</link>,
- <link linkend="ThisCell5">ThisCell(5)</link>,
- <link linkend="fs_newcell1">fs_newcell(1)</link></para>
-
- </refsect1>
- <refsect1>
- <title>Copyright</title>
- <para>IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.</para>
-
- <para>This documentation is covered by the IBM Public License Version 1.0. It was
- converted from HTML to POD by software written by Chas Williams and Russ
- Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.</para>
-
- </refsect1>
- </refentry>
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