FS_CHECKSERVERS(1)					       AFS Command Reference						FS_CHECKSERVERS(1)

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:

       o   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.

       o   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:

       o   By default, only machines that are marked inaccessible and belong to the local cell (the cell listed in the local /etc/openafs/ThisCell
	   file).

       o   If the -cell argument is included, only machines that are marked inaccessible and belong to the specified cell.

       o   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:

	   o   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.

	   o   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 "stateu.edu" cell:

	  % fs checkservers -cell stateu.edu
	  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.abc.com SV3.STATE.EDU.

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 							    2012-03-26							FS_CHECKSERVERS(1)