scsimgr SCSI Management and Diagnostics utility on HP-UX 11i v3 (March 2008)

default = 30
saved =
disk15 and disk16 inherit current and default values from the “/escsi/esdisk” settable attribute scope,
which covers all devices bound to the esdisk class driver.
You can change the value of esd_secs at “/escsi/esdisk” level to 60 and check that the new value is
updated for disk15 and disk16 without having to open these devices.
# scsimgr set_attr -N /escsi/esdisk -a esd_secs=60
Value of attribute esd_secs set successfully
#scsimgr get_attr -N /escsi/esdisk -a esd_secs
SCSI ATTRIBUTES FOR DDR ENTRY : /escsi/esdisk
name = esd_secs
current = 60
default = 30
saved =
# scsimgr get_attr -D /dev/rdisk/disk15 -a esd_secs -a state
SCSI ATTRIBUTES FOR LUN : /dev/rdisk/disk15
name = esd_secs
current = 60
default = 60
saved =
name = state
current = UNOPEN
default =
saved =
# scsimgr get_attr –D /dev/rdisk/disk16 -a esd_secs -a state
SCSI ATTRIBUTES FOR LUN : /dev/rdisk/disk16
name = esd_secs
current = 60
default = 60
saved =
name = state
current = UNOPEN
default =
saved =
Fine tuning the SCSI stack to interoperate with devices with different operational
requirements
This use case shows how the tunable architecture can be used to fine tune interoperability with
devices.
The SCSI stack defines the following tunables for disk devices bound to the esdisk class driver:
• path_fail_secs: Timeout in seconds before declaring a lunpath offline when the device no
longer responds to I/O requests sent through this I/O path. The default value is 120
seconds.
• max_q_depth: Maximum number of concurrent I/O requests that can be sent to the device
on a given I/O path. The default value is 8.
• load_bal_policy: Policy used to distribute I/O requests between lunpaths of a device. The
default policy is round_robin (I/Os are distributed between I/O paths to the device in a
round robin manner).
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