fs_getserverprefs - Displays preference ranks for file servers or VL servers
<output to named file
<output to named file
<output to named file
The fs getserverprefs
command displays preference ranks for file server
machine interfaces (file server machines run the fs
process) or, if the
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 preferred.
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
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
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
- -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
- 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 are ignored.
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
This can significantly speed the production of output.
By default, the command writes to the standard output stream. Use the
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
, 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
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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