stager.cmd - Defines SAM-QFS stager directives
Directives for controlling the SAM-QFS stager are read from
/etc/opt/SUNWsamfs/stager.cmd. In the stager.cmd file, each
directive must appear on its own line. Each directive has
the following format:
keyword = value
Comment lines can appear in the stager.cmd file. A pound
sign (#) in column 1 indicates a comment line.
The stager.cmd file accepts the following directives:
directio = on|off
Set the file reading method for staging. The
directive on will set direct I/O for all staging
if file size is equal to or greater than
dio_min_size. off will cause paged I/O to be used.
The default is on.
NOTE: Staging on a shared QFS file system always
uses direct I/O.
dio_min_size = n
If the file size is < n megabytes, the stager will
use paged I/O for non-shared QFS file systems. The
default is 8 megabytes. If directio = off all
stage io is paged.
NOTE: dio_min_size is ignored for shared QFS file
systems which always use direct I/O.
drives = library count
Sets the number of drives to use for staging on
media library library to a number specified by
count. The default value is the actual number of
drives in library.
The library specified must be the family set name
of a media library as defined in the mcf file. If
this directive is specified, the stager uses only
count number of drives in the media library to
stage archive copies. This directive prevents the
stager from using all drives in a media library
and possibly interfering with archiving.
For example, the following directive specifies
that 3 drives should be used for staging in an
ADIC/Grau media library.
drives = gr50 3
bufsize = media buffer_size [ lock ]
Sets the stage buffer size for a specific media
For media, specify a media type from the mcf(4)
For buffer_size, specify an integer value in the
range 2 < buffer_size < 8192. The default is 16.
The buffer_size specified is multiplied by the
default block size for media. For more
information on default block sizes, see the
dev_blksize description on the defaults.conf(4)
If lock is specified, the stager locks the stage
buffer in memory. If the stage buffer is locked,
system CPU time can be reduced.
logfile = filename [event]
Sets the name of the stager log file to filename,
specified as an absolute pathname. By default, no
log file is written. event is start, finish,
cancel, error, or all. The default is finish,
cancel, and error.
The stager log file contains a line for each file
staged. The line contains the event type, date,
time, media, VSN, inode generation number of the
file, position and offset of where the file is
stored, name of the file, copy number, user id,
group id, requestor's user id, equipment number of
the drive upon which the file was staged, and the
type of stage, 'V' for data verify and '-' for
maxactive = number
Sets the maximum number of stage requests that can
be active at one time in the stager to an integer
number. The minimum number is 1. The default
number is based on memory size, 5000 per gigabyte.
The maximum number is 500000.
The number of outstanding stage requests has a
direct impact on incore inode usage, since each
request requires an incore inode for the duration
of the stage. Sites may wish to increase the
default number of incore inodes if they greatly
increase the maximum number of stage requests.
This can be done by setting ninodes in the
/etc/system file, as shown in the following
For more information on ninodes, see the Sun QFS
File System Configuration and Administration
maxretries = number
Sets the maximum number of stage retries attempted
per archive copy when certain errors are
encountered to an integer number. The minimum
number is 0. The default number is 3. The
maximum number is 20.
copysel = n1:n2:n3:n4
Sets the copy selection sequence for staging. n?
must be a range of 1 <= n? <= 4. By default,
1:2:3:4 is defined, so copy number 1, 2, 3 then 4
is selected for staging if stage is not initiated
by stage(1) and copy number is not specified by -c
Four copies, n1 to n4, must be defined, even if
there are less than four copies available.
fs = file_system_family_set_name
Specifies that the subsequent directives apply to
the indicated file_system_family_set_name only
until stream definition is met. File system
specific directives override general directives.
NOTE: Currently, only copysel definition can be
defined for the specific file system.
STREAM DEFINITIONS SECTION
The streams and endstreams directives delimit this section
of the stager.cmd file.
Each line begins with the media type followed by the
definitions. The syntax for this line is as follows:
media The media type. Currently, only 'dk' is supported.
Set the maximum size of the stream to size. size
may be specified with the suffixes 'b', 'k', 'M',
'G', and 'T', for bytes, kilobytes, megabytes,
gigabytes, and terabytes. The default unit size
is bytes. The default value is 1G bytes. Files
to be staged from the same stream will be added to
the same stream. If size of the stream hit the
size, new stream will be created for the VSN.
Set the maximum file count to count for the each
stream. The default value is 0. Files to be
staged from the same VSN will be added to the same
stream. If count of the file hit the count, new
stream will be created for the VSN.
If more than one of -maxsize or -maxcount are
specified, the first condition encountered creates
the new stream for VSN.
The following is an example /etc/opt/SUNWsamfs/stager.cmd
logfile = /var/opt/SUNWsamfs/log/stager
drives= hp30 1
copysel = 4:3:2:1
fs = samfs1
copysel = 3:1:4:2
dk -maxsize 2G -maxcount 10000
The results of the stager's operations are found in
/var/opt/SUNWsamfs/log/stager. For the media library
specified as hp30, the stager is allowed to use only 1 drive
for staging files. The stager selects copy number 4, 3, 2
then 1 for staging files by default. The stager selects
copy number 3, 1, 4 then 2 for staging files for the file
system samfs1. The size of stream is limited to 2G bytes,
and the maiximum file count for the each stream is limited
to 10000 for the media type dk.
The following files are used by the stager:
/etc/opt/SUNWsamfs/stager.cmd Stager command file.