arrayd - array services daemon
SYNOPSIS
arrayd [options]
DESCRIPTION
arrayd is the array services daemon. It performs several
different tasks related to the use of an array of two or
more machines, such as:
- Allocating global array session handles
- Forwarding "array commands" to all of the machines in
an array
- Maintaining a database of the current array configura
tion and providing that information to other commands
and programs
- Determining which processes belong to a particular
array session and providing that information to other
commands and programs
For more discussion of these services, see array_services(5).
The arrayd command itself has several command line options. The
valid options include:
-c "Check": causes arrayd to read any configuration files
then exit immediately, sending any errors to stderr rather
than syslog (which is the usual behavior). This is pri
marily of use for checking the validity of new configura
tion files. This is the same as the --qqff flag.
-f filename
Specifies the name of a single configuration file. This
option may be specified more than once, in which case the
files will be processed in the order that they are speci
fied. One reason to have multiple configuration files
would be to allow all of the machines in an array to use a
single file (accessed via NFS, perhaps) for array entries
and still maintain private configuration files for local
options and/or security information. The format of an
arrayd configuration file is described in arrayd.conf(4).
If no configuration files are specified, then
"/usr/lib/array/arrayd.conf" and
"/usr/lib/array/arrayd.auth" will both be used (in that
order).
-m number
Sets the "machine identifier" used by the array services
ber. Certain versions of the IRIX kernel may also use
this value when generating array session handles. number
must be a value between 0 and 32767. It will override any
IDENT setting in the LOCAL section of any configuration
file.
-mt number
Sets the time interval for arrayd deamon to check whether
any mpi job has died. If any mpi job dies arrayd will
clean up the children of that mpi job. The time interval
is in second and it can be any number between 0 and 32767.
The default time interval is 10 (sec).
-n Ordinarily, arrayd will automatically "daemonize" itself,
that is, dissociate itself from the current terminal and
place itself in the background. Specifying this option
will cause arrayd to run in the foreground on the current
terminal. This is mostly useful for testing purposes.
-nf Do not read any configuration files. This is most useful
with options like --ssmm that cause arrayd to quit after per
forming tasks that do not require configuration informa
tion. --nnff will override any --ff options.
-nm Do not set the system machine ID. This is used to over
ride a "LOCAL OPTIONS SETMACHID" statement in the configu
ration file.
-p number
This specifies which port the array services daemon should
listen on for requests. It will override any PORT setting
in the LOCAL section of any configuration file.
-qf Quit after parsing the configuration file(s). This is the
same as the --cc option.
-qm Quit after setting the system machine ID. Causes arrayd
to exit as soon as it has set the system machine identi
fier (or would have done so, in the case where this opera
tion is not supported by the current OS release). This
may be useful in cases where a non-default system machine
identifier is desired, but none of the other array ser
vices provided by arrayd are needed. This can also be
used to change the machine identifier on a system that is
already running another copy of arrayd; in this case, ker
nel-generated array session handles will use the new
machine identifier while those generated by arrayd will
continue to use the original machine identifier.
-sm Some versions of IRIX permit setting a system "machine
identifier", which is used by the kernel for generating
global array session handles. If the current system has
this facility and --ssmm is specified, arrayd will set the
ment in the configuration file or on the command line
using the --mm option.
-v "Verbose": the daemon will run in the foreground (as with
the -n option) and will send any error messages, plus some
additional messages, to stderr rather than syslog. Speci
fying this option more than once or specifying more than
one "v" (for example "-vvv") will cause additional debug
ging information to be generated.
To clean up errorlog file at a specific time interval the user
needs to set two variables before running arrayd; they are
ARRAYD_ELCHECK and ARRAYD_ELAGE. The ARRAYD_ELCHECK variable
defines the interval, in seconds, that arrayd uses to check for
files in the "/tmp/.arraysvcs" directory. The ARRAYD_ELAGE vari
able, also in seconds, defines the interval that arrayd uses to
check the age of the files in the "/tmp/.arraysvcs" directory and
remove files that are too old.
The default value for ARRAYD_ELCHECK is 3600 seconds (1hr). The
default value for ARRAYD_ELAGE is 86400 seconds (24hrs).
On larger systems with 128 processors or more, this tmp directory
may not be cleared often enough, causing permission problems with
the special files located therein. In this case, it is recom
mended that lower values for ARRAYD_ELCHECK and ARRAYD_ELAGE be
used. For example, setting these variables to half of the
default values - 1800 and 43200 respectively - will clear this
tmp directory more frequently and should resolve most permission
problems of this type.
The system administrator can define these two variables before
the call to arrayd in the "/etc/init.d/array" script, then stop
and restart arrayd.
If you want to run jobs through arrayd across a large cluster,
where there might be a lot of congestion on the network, you
might want to tune ARRAYD_CONNECTTO and ARRAYD_TIMEOUT variables.
By default, these two variables are set to 5 seconds and 45 sec
onds, respectively. If there is a possible network congestion,
you might want to set these two variables higher than default
setting. This might slow down some array commands when a host is
unavailable but it will help to prevent MPI start up problems due
to connection time-out.
NOTES
arrayd can be set up to run automatically at system ini
tialization time by using the chkconfig(1M) command to
turn on the array feature:
cchhkkccoonnffiigg aarrrraayy oonn
options from the file /etc/config/arrayd.options.
SEE ALSO
array(1), arrayd.conf(4), array_services(5).
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