HP-UX Reference (11i v1 00/12) - 1M System Administration Commands A-M (vol 3)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man1m/!!!intro.1m
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d
dcc(1M) dcc(1M)
NAME
dcc - control read and write caching for HP SCSI disk array drives
SYNOPSIS
dcc [options][drive_list] device_file
DESCRIPTION
dcc displays or changes the read-ahead caching status, and write-immediate reporting status of selected
drives on the HP SCSI disk array referenced by device_file.
Options
-d Display only. Displays the read-ahead caching and write immediate reporting
status of all selected drives on the HP SCSI disk array. For HP C2430 disk array
devices, the number and size of cache segments is displayed. This option cannot
be used with any other option.
-ron Read on. Enables read-ahead caching on all selected drives of the HP SCSI disk
array. Can be used in combination with one of the write-immediate reporting
options.
-roff Read off. Disables read-ahead caching on all selected drives of the
HP SCSI disk
array. Can be used in combination with one of the write-immediate reporting
options.
-won Write on. Enables write-immediate reporting on all selected drives of the
HP SCSI
disk array. Can be used in combination with one of the read-ahead caching
options.
-woff Write off. Disables write immediate reporting on all selected drives of the
HP
SCSI
disk array. Can be used in combination with one of the read-ahead caching
options.
-snum_segments Set the number of cache segments. This option is unique to the HP C2430 disk
array. The disk mechanism cache can be segmented into 1, 2, 4, 8 or 16 seg-
ments. The default is 2 segments. This option cannot be used with other options.
drive_list Specify a set of drives. If this optional list is absent, the default set of affected
drives is all drives attached to the controller. The list is in the form
cXiY,...
where X (a decimal number) represents
SCSI channel number, and Y (a decimal
number) represents the SCSI ID of the drive. Multiple drives in the list are
separated by commas.
RETURN VALUE
dcc returns the following values:
0 Successful completion.
-1 Command failed (an error occurred).
ERROR MESSAGES
Errors can originate from problems with:
• dcc
• SCSI (device level) communications
• system calls
Error messages generated by dcc:
usage: dcc options [cXiY,...] <special>
An error in command syntax has occurred. Enter command again with the required arguments, in
the order shown.
dcc: Arg out of range
One of the arguments is larger than its allowed maximum value (or smaller than its allowed minimum
value), or is incorrect in form. Check the size, and form of each argument and make appropriate
corrections.
dcc: device busy
To ensure that dcc does not modify a disk array that is being used by another process,
dcc
Section 1M−−154 − 1 − HP-UX Release 11i: December 2000
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