Overview: The Next Generation Mass Storage Stack (September 2009)

Legacy Device Special Files and Hardware Paths
As of HP-UX 11i v3, the legacy view is deprecated, and all its components—naming conventions, DSFs, and
hardware paths—will be obsoleted in future versions of HP-UX.
Tunable Kernel Parameters
The following tunable kernel parameters related to mass storage are obsolete in HP-UX 11i v3:
scsi_max_qdepth
Controls the maximum number of I/O operations that a LUN can queue up for execution. It
has been replaced with the max_q_depth scsimgr attribute. To change the queue
depth on a LUN, enter the following command:
# scsimgr set_attr -D device_file –a max_q_depth=new_value
For example, to set the queue depth for disk14 to 32, enter the following:
# scsimgr set_attr -D /dev/rdisk/disk14 -a max_q_depth=32
To set the queue depth to 8 persistently for all LUNs on the system, enter the following:
# scsimgr save_attr –N /escsi/esdisk –a max_q_depth=8
scsi_max_phys
Sets the maximum data size the SCSI subsystem accepts for an I/O request. It has been
replaced with the escsi_maxphys scsimgr attribute. For example, to set the maximum
data size persistently to 64 4KB pages, enter the following command:
# scsimgr save_attr –a escsi_maxphys=64
default_disk_ir
Enables or disables the use of a device write cache, also known as immediate reporting. It
has been replaced with the immediate_report parameter to the scsictl command.
To disable immediate reporting for a SCSI device on the system, enter the following
command:
# scsictl –m immediate_report=0 device_file
To disable immediate reporting for a set of disks based on vendor id, product id, and/or
firmware revision, use the scsimgr command to set the disable_flags attribute of the
esdisk driver. This attribute can be set at any settable attribute scope to control a number
of functions including write cache enable (WCE). For example, to persistently disable write
cache and 16 bytes read/write CDBs on all disks managed by the esdisk driver, enter
the following command:
# scsimgr save_attr –N /escsi/esdisk –a disable_flags=”WCE RW16”
For more information about settable attribute scope, see scsimgr(1M) and for the
disable_flags attribute, see scsimgr_esdisk(7).
Changes to Existing Procedures
Most I/O operations in HP-UX 11i v3 are no different from HP-UX 11i v2. To enable the agile view for a
command, you may need to specify a command-line option such as –N for ioscan or toggle a button in a GUI.
However, you perform the following three tasks differently in HP-UX 11i v3:
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