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. L<fs_setserverprefs(1)> explains how the Cache Manager
37 sets default ranks, and how to use that command to change the default
40 Default VL Server ranks range from 10,000 to 10,126. The Cache Manager
41 assigns ranks to every machine listed in its copy of the
42 F</usr/vice/etc/CellServDB> file or found via DNS AFSDB or SRV records for
43 the cell when it initializes. When the Cache Manager needs to fetch VLDB
44 information from a cell, it compares the ranks for the VL Server machines
45 belonging to that cell, and attempts to contact the VL Server with the
46 lowest integer rank. If the Cache Manager cannot reach the VL Server
47 (because of server process, machine or network outage), it tries to
48 contact the VL Server with the next lowest integer rank, and so on. If all
49 of a cell's VL Server machines are unavailable, the Cache Manager cannot
50 fetch data from the cell.
52 Default file server ranks range from 5,000 to 40,000, excluding the range
53 used for VL Servers (10,000 to 10,126); the maximum possible rank is
54 65,534. When the Cache Manager needs to fetch data from a volume, it
55 compares the ranks for the interfaces of machines that house the volume,
56 and attempts to contact the interface that has the lowest integer rank. If
57 it cannot reach the B<fileserver> process via that interface (because of
58 server process, machine or network outage), it tries to contact the
59 interface with the next lowest integer rank, and so on. If it cannot reach
60 any of the interfaces for machines that house the volume, it cannot fetch
63 For both file server machines and VL Server machines, it is possible for a
64 machine or interface in a foreign cell to have the same rank as a machine
65 or interface in the local cell. This does not present a problem, because
66 the Cache Manager only ever compares ranks for machines belonging to one
73 =item B<-file> <I<output file>>
75 Specifies the full pathname of a file to which to write the preference
76 ranks. If the specified file already exists, the command overwrites its
77 contents. If the pathname is invalid, the command fails. If this argument
78 is not provided, the preference ranks appear on the standard output
83 Displays the IP addresses of file server machine interfaces or VL Server
84 machines, rather than their hostnames. If this argument is not provided,
85 the B<fs> command interpreter has the IP addresses translated to hostnames
86 such as C<fs1.example.com>.
90 Displays preference ranks for VL Server machines rather than file server
95 Prints the online help for this command. All other valid options are
102 The output consists of a separate line for each file server machine
103 interface or VL Server machine, pairing the machine's hostname or IP
104 address with its rank. The Cache Manager stores IP addresses in its kernel
105 list of ranks, but the command by default identifies interfaces by
106 hostname, by calling a translation routine that refers to either the
107 cell's name service (such as the Domain Name Server) or the local host
108 table. If an IP address appears in the output, it is because the
109 translation attempt failed. To bypass the translation step and display IP
110 addresses rather than hostnames, include the B<-numeric> flag. This can
111 significantly speed the production of output.
113 By default, the command writes to the standard output stream. Use the
114 B<-file> argument to write the output to a file instead.
118 The following example displays the local Cache Manager's preference ranks
119 for file server machines. The local machine belongs to the AFS cell named
120 B<example.com>, and in this example the ranks of file server machines in its
121 local cell are lower than the ranks of file server machines from the
122 foreign cell, C<example.net>. It is not possible to translate the IP addresses
123 of two machines on the 138.255 network.
126 fs2.example.com 20007
127 fs3.example.com 30002
128 fs1.example.com 20011
129 fs4.example.com 30010
130 server1.example.net 40002
132 server6.example.net 40012
135 The following example shows hows the output displays IP addresses when the
136 B<-numeric> flag is included, and illustrates how network proximity
137 determines default ranks (as described on the B<fs setserverprefs>
138 reference page). The local machine has IP address 192.12.107.210, and the
139 two file server machines on its subnetwork have ranks of 20,007 and
140 20,011. The two file server machines on a different subnetwork of the
141 local machine's network have higher ranks, 30,002 and 30,010, whereas the
142 ranks of the remaining machines range from 40,000 to 40,012 because they
143 are in a completely different network.
145 % fs getserverprefs -numeric
155 The example shows how the B<-vlservers> flag displays preference ranks for
158 % fs getserverprefs -vlservers
159 fs2.example.com 10052
160 fs3.example.com 10113
161 fs1.example.com 10005
163 =head1 PRIVILEGE REQUIRED
169 L<fs_setserverprefs(1)>
173 IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.
175 This documentation is covered by the IBM Public License Version 1.0. It was
176 converted from HTML to POD by software written by Chas Williams and Russ
177 Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.