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<H1>Administration Reference</H1>
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<P>
<H2><A NAME="HDRFS_GETSERVERPREFS" HREF="auarf002.htm#ToC_160">fs getserverprefs</A></H2>
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<P><STRONG>Purpose</STRONG>
<P>Displays the Cache Manager's preference ranks for file server or VL
Server machines
<P><STRONG>Synopsis</STRONG>
<PRE><B>fs getserverprefs</B> [<B>-file</B> <<VAR>output to named file</VAR>>]
[<B>-numeric</B>] [<B>-vlservers</B>] [<B>-help</B>]
<B>fs gets</B> [<B>-f</B> <<VAR>output to named file</VAR>>] [<B>-n</B>] [<B>-v</B>] [<B>-h</B>]
<B>fs gp</B> [<B>-f</B> <<VAR>output to named file</VAR>>] [<B>-n</B>] [<B>-v</B>] [<B>-h</B>]
</PRE>
<P><STRONG>Description</STRONG>
<P>The <B>fs getserverprefs</B> command displays preference ranks for file
server machine interfaces (file server machines run the <B>fs</B> process)
or, if the <B>-vlserver</B> flag is provided, for Volume Location (VL)
Server machines (which run the <B>vlserver</B> process). For file
server machines, the Cache Manager tracks up to 15 interfaces per machine and
assigns a separate rank to each interface. The ranks indicate the order
in which the local Cache Manager attempts to contact the interfaces of
machines that are housing a volume when it needs to fetch data from the
volume. For VL Server machines, the ranks indicate the order in which
the Cache Manager attempts to contact a cell's VL Servers when requesting
VLDB information. For both types of rank, lower integer values are more
preferred.
<P>The Cache Manager stores ranks in kernel memory. Once set, a rank
persists until the machine reboots, or until the <B>fs setserverprefs</B>
command is used to change it. The reference page for the <B>fs
setserverprefs</B> command explains how the Cache Manager sets default
ranks, and how to use that command to change the default values.
<P>Default VL Server ranks range from 10,000 to 10,126, and the Cache Manager
assigns them to every machine listed in its copy of the
<B>/usr/vice/etc/CellServDB</B> file. When the Cache Manager needs
to fetch VLDB information from a cell, it compares the ranks for the VL Server
machines belonging to that cell, and attempts to contact the VL Server with
the lowest integer rank. If the Cache Manager cannot reach the VL
Server (because of server process, machine or network outage), it tries to
contact the VL Server with the next lowest integer rank, and so on. If
all of a cell's VL Server machines are unavailable, the Cache Manager
cannot fetch data from the cell.
<P>Default file server ranks range from 5,000 to 40,000, excluding the range
used for VL Servers (10,000 to 10,126); the maximum possible rank is
65,534. When the Cache Manager needs to fetch data from a volume, it
compares the ranks for the interfaces of machines that house the volume, and
attempts to contact the interface that has the lowest integer rank. If
it cannot reach the <B>fileserver</B> process via that interface (because
of server process, machine or network outage), it tries to contact the
interface with the next lowest integer rank, and so on. If it cannot
reach any of the interfaces for machines that house the volume, it cannot
fetch data from the volume.
<P>For both file server machines and VL Server machines, it is possible for a
machine or interface in a foreign cell to have the same rank as a machine or
interface in the local cell. This does not present a problem, because
the Cache Manager only ever compares ranks for machines belonging to one cell
at a time.
<P><STRONG>Options</STRONG>
<DL>
<P><DT><B>-file
</B><DD>Specifies the full pathname of a file to which to write the preference
ranks. If the specified file already exists, the command overwrites its
contents. If the pathname is invalid, the command fails. If this
argument is not provided, the preference ranks appear on the standard output
stream.
<P><DT><B>-numeric
</B><DD>Displays the IP addresses of file server machine interfaces or VL Server
machines, rather than their hostnames. If this argument is not
provided, the <B>fs</B> command interpreter has the IP addresses
translated to hostnames such as <B>fs1.abc.com</B>.
<P><DT><B>-vlservers
</B><DD>Displays preference ranks for VL Server machines rather than file server
machine interfaces.
<P><DT><B>-help
</B><DD>Prints the online help for this command. All other valid options
are ignored.
</DL>
<P><STRONG>Output</STRONG>
<P>The output consists of a separate line for each file server machine
interface or VL Server machine, pairing the machine's hostname or IP
address with its rank. The Cache Manager stores IP addresses in its
kernel list of ranks, but the command by default identifies interfaces by
hostname, by calling a translation routine that refers to either the
cell's name service (such as the Domain Name Server) or the local host
table. If an IP address appears in the output, it is because the
translation attempt failed. To bypass the translation step and display
IP addresses rather than hostnames, include the <B>-numeric</B>
flag. This can significantly speed the production of output.
<P>By default, the command writes to the standard output stream. Use
the <B>-file</B> argument to write the output to a file instead.
<P><STRONG>Examples</STRONG>
<P>The following example displays the local Cache Manager's preference
ranks for file server machines. The local machine belongs to the AFS
cell named <B>abc.com</B>, and in this example the ranks of file
server machines in its local cell are lower than the ranks of file server
machines from the foreign cell, <B>def.com</B>. It is not
possible to translate the IP addresses of two machines on the 138.255
network.
<PRE> % <B>fs getserverprefs</B>
fs2.abc.com 20007
fs3.abc.com 30002
fs1.abc.com 20011
fs4.abc.com 30010
server1.def.com 40002
138.255.33.34 40000
server6.def.com 40012
138.255.33.37 40005
</PRE>
<P>The following example shows hows the output displays IP addresses when the
<B>-numeric</B> flag is included, and illustrates how network proximity
determines default ranks (as described on the <B>fs setserverprefs</B>
reference page). The local machine has IP address
192.12.107.210, and the two file server machines on its
subnetwork have ranks of 20,007 and 20,011. The two file server
machines on a different subnetwork of the local machine's network have
higher ranks, 30,002 and 30,010, whereas the ranks of the remaining machines
range from 40,000 to 40,012 because they are in a completely different
network.
<PRE> % <B>fs getserverprefs -numeric</B>
192.12.107.214 20007
192.12.105.99 30002
192.12.107.212 20011
192.12.105.100 30010
138.255.33.41 40002
138.255.33.34 40000
138.255.33.36 40012
138.255.33.37 40005
</PRE>
<P>The example shows how the <B>-vlservers</B> flag displays preference
ranks for VL Server machines:
<PRE> % <B>fs getserverprefs -vlservers</B>
fs2.abc.com 10052
fs3.abc.com 10113
fs1.abc.com 10005
</PRE>
<P><STRONG>Privilege Required</STRONG>
<P>None
<P><STRONG>Related Information</STRONG>
<P><A HREF="auarf162.htm#HDRFS_SETSERVERPREFS">fs setserverprefs</A>
<P>
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