3 fs getserverprefs - Displays preference ranks for file servers or VL servers
10 B<fs getserverprefs> S<<< [B<-file> <I<output to named file>>] >>>
11 [B<-numeric>] [B<-vlservers>] [B<-help>]
13 B<fs gets> S<<< [B<-f> <I<output to named file>>] >>> [B<-n>] [B<-v>] [B<-h>]
15 B<fs gp> S<<< [B<-f> <I<output to named file>>] >>> [B<-n>] [B<-v>] [B<-h>]
22 The B<fs getserverprefs> command displays preference ranks for file server
23 machine interfaces (file server machines run the B<fs> process) or, if the
24 B<-vlserver> flag is provided, for Volume Location (VL) Server machines
25 (which run the B<vlserver> process). For file server machines, the Cache
26 Manager tracks up to 15 interfaces per machine and assigns a separate rank
27 to each interface. The ranks indicate the order in which the local Cache
28 Manager attempts to contact the interfaces of machines that are housing a
29 volume when it needs to fetch data from the volume. For VL Server
30 machines, the ranks indicate the order in which the Cache Manager attempts
31 to contact a cell's VL Servers when requesting VLDB information. For both
32 types of rank, lower integer values are more preferred.
34 The Cache Manager stores ranks in kernel memory. Once set, a rank persists
35 until the machine reboots, or until the B<fs setserverprefs> command is
36 used to change it. The reference page for the B<fs setserverprefs> command
37 explains how the Cache Manager sets default ranks, and how to use that
38 command to change the default values.
40 Default VL Server ranks range from 10,000 to 10,126, and the Cache Manager
41 assigns them to every machine listed in its copy of the
42 F</usr/vice/etc/CellServDB> file. When the Cache Manager needs to fetch
43 VLDB information from a cell, it compares the ranks for the VL Server
44 machines belonging to that cell, and attempts to contact the VL Server
45 with the lowest integer rank. If the Cache Manager cannot reach the VL
46 Server (because of server process, machine or network outage), it tries to
47 contact the VL Server with the next lowest integer rank, and so on. If all
48 of a cell's VL Server machines are unavailable, the Cache Manager cannot
49 fetch data from the cell.
51 Default file server ranks range from 5,000 to 40,000, excluding the range
52 used for VL Servers (10,000 to 10,126); the maximum possible rank is
53 65,534. When the Cache Manager needs to fetch data from a volume, it
54 compares the ranks for the interfaces of machines that house the volume,
55 and attempts to contact the interface that has the lowest integer rank. If
56 it cannot reach the B<fileserver> process via that interface (because of
57 server process, machine or network outage), it tries to contact the
58 interface with the next lowest integer rank, and so on. If it cannot reach
59 any of the interfaces for machines that house the volume, it cannot fetch
62 For both file server machines and VL Server machines, it is possible for a
63 machine or interface in a foreign cell to have the same rank as a machine
64 or interface in the local cell. This does not present a problem, because
65 the Cache Manager only ever compares ranks for machines belonging to one
72 =item B<-file> <I<output file>>
74 Specifies the full pathname of a file to which to write the preference
75 ranks. If the specified file already exists, the command overwrites its
76 contents. If the pathname is invalid, the command fails. If this argument
77 is not provided, the preference ranks appear on the standard output
82 Displays the IP addresses of file server machine interfaces or VL Server
83 machines, rather than their hostnames. If this argument is not provided,
84 the B<fs> command interpreter has the IP addresses translated to hostnames
85 such as C<fs1.abc.com>.
89 Displays preference ranks for VL Server machines rather than file server
94 Prints the online help for this command. All other valid options are
101 The output consists of a separate line for each file server machine
102 interface or VL Server machine, pairing the machine's hostname or IP
103 address with its rank. The Cache Manager stores IP addresses in its kernel
104 list of ranks, but the command by default identifies interfaces by
105 hostname, by calling a translation routine that refers to either the
106 cell's name service (such as the Domain Name Server) or the local host
107 table. If an IP address appears in the output, it is because the
108 translation attempt failed. To bypass the translation step and display IP
109 addresses rather than hostnames, include the B<-numeric> flag. This can
110 significantly speed the production of output.
112 By default, the command writes to the standard output stream. Use the
113 B<-file> argument to write the output to a file instead.
117 The following example displays the local Cache Manager's preference ranks
118 for file server machines. The local machine belongs to the AFS cell named
119 B<abc.com>, and in this example the ranks of file server machines in its
120 local cell are lower than the ranks of file server machines from the
121 foreign cell, C<def.com>. It is not possible to translate the IP addresses
122 of two machines on the 138.255 network.
129 server1.def.com 40002
131 server6.def.com 40012
134 The following example shows hows the output displays IP addresses when the
135 B<-numeric> flag is included, and illustrates how network proximity
136 determines default ranks (as described on the B<fs setserverprefs>
137 reference page). The local machine has IP address 192.12.107.210, and the
138 two file server machines on its subnetwork have ranks of 20,007 and
139 20,011. The two file server machines on a different subnetwork of the
140 local machine's network have higher ranks, 30,002 and 30,010, whereas the
141 ranks of the remaining machines range from 40,000 to 40,012 because they
142 are in a completely different network.
144 % fs getserverprefs -numeric
154 The example shows how the B<-vlservers> flag displays preference ranks for
157 % fs getserverprefs -vlservers
162 =head1 PRIVILEGE REQUIRED
168 L<fs_setserverprefs(1)>
172 IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.
174 This documentation is covered by the IBM Public License Version 1.0. It was
175 converted from HTML to POD by software written by Chas Williams and Russ
176 Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.