fs_getserverprefs - Displays preference ranks for file servers or VL
fs getserverprefs [-file <output to named file>]
[-numeric] [-vlservers] [-help]
fs gets [-f <output to named file>] [-n] [-v] [-h]
fs gp [-f <output to named file>] [-n] [-v] [-h]
The fs getserverprefs command displays preference ranks for file server
machine interfaces (file server machines run the fs process) or, if the
-vlserver flag is provided, for Volume Location (VL) Server machines
(which run the vlserver 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
The Cache Manager stores ranks in kernel memory. Once set, a rank
persists until the machine reboots, or until the fs setserverprefs
command is used to change it. fs_setserverprefs(1) explains how the
Cache Manager sets default ranks, and how to use that command to change
the default values.
Default VL Server ranks range from 10,000 to 10,126. The Cache Manager
assigns ranks to every machine listed in its copy of the
/etc/openafs/CellServDB file or found via DNS AFSDB or SRV records for
the cell when it initializes. 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.
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 fileserver 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.
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.
-file <output file>
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.
Displays the IP addresses of file server machine interfaces or VL
Server machines, rather than their hostnames. If this argument is
not provided, the fs command interpreter has the IP addresses
translated to hostnames such as "fs1.abc.com".
Displays preference ranks for VL Server machines rather than file
server machine interfaces.
Prints the online help for this command. All other valid options
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 -numeric flag. This can
significantly speed the production of output.
By default, the command writes to the standard output stream. Use the
-file argument to write the output to a file instead.
The following example displays the local Cache Manager's preference
ranks for file server machines. The local machine belongs to the AFS
cell named abc.com, 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, "def.com". It is not possible to
translate the IP addresses of two machines on the 138.255 network.
% fs getserverprefs
The following example shows hows the output displays IP addresses when
the -numeric flag is included, and illustrates how network proximity
determines default ranks (as described on the fs setserverprefs
reference page). The local machine has IP address 126.96.36.199, 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.
% fs getserverprefs -numeric
The example shows how the -vlservers flag displays preference ranks for
VL Server machines:
% fs getserverprefs -vlservers
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