HP-UX Reference (11i v2 03/08) - 5 Miscellaneous Topics, 7 Device (Special) Files, 9 General Information, Index (vol 9)

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scsi_maxphys(5) scsi_maxphys(5)
(Tunable Kernel Parameters)
NAME
scsi_maxphys - maximum allowed length of an I/O on all SCSI devices
VALUES
Failsafe
1048576
Default
1024*1024
Allowed values
1048576 (16777215 and 33554432 for V-Class systems)
Recommended values
1048576 (16777215 for V-Class systems)
DESCRIPTION
This tunable sets the maximum data size the SCSI subsystem will accept for an I/O. Depending on the
device’s characteristics and the device driver configuration, the maximum size allowed by the SCSI sub-
system for a particular SCSI device might be lower than or equal to this tunable’s value. It will never be
greater.
Who Is Expected to Change This Tunable?
Any customer.
Restrictions on Changing
Changes to this tunable will take effect when the device is first opened.
When Should the Value of This Tunable Be Raised?
The value should never be raised except on V-Class systems where it can be raised to 32 MB.
When Should the Value of This Tunable Be Lowered?
The value should never be lowered.
What Other Tunables Should Be Changed at the Same Time as This One?
None.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its
meaning changed in future releases of HP-UX.
AUTHOR
scsi_maxphys was developed by HP.
HP-UX 11i Version 2: August 2003 − 1 − Hewlett-Packard Company Section 5−−255