Provided by: openafs-client_1.8.13.2-1ubuntu1_amd64 
NAME
fs_checkservers - Displays the status of server machines
SYNOPSIS
fs checkservers [-cell <cell to check>] [-all] [-fast]
[-interval <seconds between probes>] [-help]
fs checks [-c <cell to check>] [-a] [-f]
[-i <seconds between probes>] [-h]
DESCRIPTION
The fs checkservers command reports whether certain AFS server machines are accessible from the local
client machine. The machines belong to one of two classes, and the Cache Manager maintains a list of them
in kernel memory:
• The database server machines for every cell listed in the local /etc/openafs/CellServDB file, plus
any machines added to the memory list by the fs newcell command since the last reboot.
• All file server machines the Cache Manager has recently contacted, and which it probably needs to
contact again soon. In most cases, the Cache Manager holds a callback on a file or volume fetched
from the machine.
If the Cache Manager is unable to contact the vlserver process on a database server machine or the
fileserver process on a file server machine, it marks the machine as inaccessible. (Actually, if a file
server machine is multihomed, the Cache Manager attempts to contact all of the machine's interfaces, and
only marks the machine as down if the fileserver fails to reply via any of them.) The Cache Manager then
periodically (by default, every three minutes) sends a probe to each marked machine, to see if it is
still inaccessible. If a previously inaccessible machine responds, the Cache Manager marks it as
accessible and no longer sends the periodic probes to it.
The fs checkservers command updates the list of inaccessible machines by having the Cache Manager probe a
specified set of them:
• By default, only machines that are marked inaccessible and belong to the local cell (the cell listed
in the local /etc/openafs/ThisCell file).
• If the -cell argument is included, only machines that are marked inaccessible and belong to the
specified cell.
• If the -all flag is included, all machines marked inaccessible.
If the -fast flag is included, the Cache Manager does not probe any machines, but instead reports the
results of the most recent previous probe.
To set the interval between probes rather than produce a list of inaccessible machines, use the -interval
argument. The non-default setting persists until the machine reboots; to preserve it across reboots, put
the appropriate fs checkservers command in the machine's AFS initialization files.
CAUTIONS
The command can take quite a while to complete, if a number of machines do not respond to the Cache
Manager's probe. The Cache Manager probes machines sequentially and waits a standard timeout period
before marking the machine as unresponsive, to allow for slow network communication. To make the command
shell prompt return quickly, put the command in the background. It is harmless to interrupt the command
by typing Ctrl-C or another interrupt signal.
Note that the Cache Manager probes only server machines marked inaccessible in its memory list. A server
machine's absence from the output does not necessarily mean that it is functioning, because it possibly
is not included in the memory list at all (if, for example, the Cache Manager has not contacted it
recently). For the same reason, the output is likely to vary on different client machines.
Unlike most fs commands, the fs checkservers command does not refer to the AFSCELL environment variable.
OPTIONS
-cell <cell to check>
Names each cell in which to probe server machines marked as inaccessible. Provide the fully qualified
domain name, or a shortened form that disambiguates it from the other cells listed in the local
/etc/openafs/CellServDB file. Combine this argument with the -fast flag if desired, but not with the
-all flag. Omit both this argument and the -all flag to probe machines in the local cell only.
-all
Probes all machines in the Cache Manager's memory list that are marked inaccessible. Combine this
argument with the -fast flag if desired, but not with the -cell argument. Omit both this flag and the
-cell argument to probe machines in the local cell only.
-fast
Displays the Cache Manager's current list of machines that are inaccessible, rather than sending new
probes. The output can as old as the current setting of the probe interval (by default three minutes,
and maximum ten minutes).
-interval <seconds between probes>
Sets or reports the number of seconds between the Cache Manager's probes to machines in the memory
list that are marked inaccessible:
• To set the interval, specify a value from the range between 1 and 600 (10 minutes); the default
is 180 (three minutes). The issuer must be logged in as the local superuser "root". The altered
setting persists until again changed with this command, or until the machine reboots, at which
time the setting returns to the default.
• Provide a value of 0 (zero) to display the current interval setting. No privilege is required. Do
not combine this argument with any other.
-help
Prints the online help for this command. All other valid options are ignored.
OUTPUT
If there are no machines marked as inaccessible, or if all of them now respond to the Cache Manager's
probe, the output is:
All servers are running.
Note that this message does not mean that all server machines in each relevant cell are running. The
output indicates the status of only those machines that the Cache Manager probes.
If a machine fails to respond to the probe within the timeout period, the output begins with the string
These servers unavailable due to network or server problems:
and lists the hostname of each machine on its own line. The Cache Manager stores machine records by
Internet address, so the format of each hostname (uppercase or lowercase letters, or an Internet address
in dotted decimal format) depends on how the local cell's name service translates it at the time the
command is issued. If a server machine is multihomed, the output lists only one of its interfaces
(usually, the currently most preferred one).
If the -interval argument is provided with a value between 1 and 600, there is no output. If the value is
0, the output reports the probe interval as follows:
The current down server probe interval is <interval> secs
EXAMPLES
The following command displays the Cache Manager's current list of unresponsive machines in the local
cell, rather than probing them again. The output indicates that if there were any machines marked
inaccessible, they all responded to the previous probe.
% fs checkservers -fast
All servers are running.
The following example probes machines in the Cache Manager's memory list that belong to the "example.org"
cell:
% fs checkservers -cell example.org
All servers are running.
The following example probes all server machines in the Cache Manager's memory list. It reports that two
machines did not respond to the probe.
% fs checkservers -all
These servers unavailable due to network or server problems:
fs1.example.com SV3.EXAMPLE.ORG.
PRIVILEGE REQUIRED
To set the probe interval, the issuer must be logged in as the local superuser "root". Otherwise, no
privilege is required.
SEE ALSO
CellServDB(5), ThisCell(5), fs_newcell(1)
COPYRIGHT
IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.
This documentation is covered by the IBM Public License Version 1.0. It was converted from HTML to POD
by software written by Chas Williams and Russ Allbery, based on work by Alf Wachsmann and Elizabeth
Cassell.
OpenAFS 2025-03-21 FS_CHECKSERVERS(1)