HP-UX 11i v3 Native Multi-Pathing for Mass Storage (August 2012)

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lunpath 16 0/2/1/0.0x500508b3009097f1.0x4014000000000000 eslpt NO_HW LUN_PATH
LUN path for disk17
lunpath 5 0/2/1/0.0x500508b3009097f9.0x4014000000000000 eslpt NO_HW LUN_PATH
LUN path for disk17
lunpath 22 0/4/1/0.0x500508b3009097f1.0x4014000000000000 eslpt CLAIMED LUN_PATH
LUN path for disk17
lunpath 13 0/4/1/0.0x500508b3009097f9.0x4014000000000000 eslpt CLAIMED LUN_PATH
LUN path for disk17
The dd command can open /dev/rdsk/c5t2d4 and transfer data even if the corresponding
lunpath is not available.
# dd if=/dev/rdsk/c5t2d4 of=/dev/null count=120
120+0 records in
120+0 records out
If leg_mpath_enable is set to false when /dev/rdsk/c5t2d4 is opened, only the lunpath
corresponding to /dev/rdsk/c5t2d4 is used. The following example shows this:
1. Disable multi-pathing for legacy DSFs of disk17, as follows:
# scsimgr set_attr -D /dev/rdisk/disk17 -a leg_mpath_enable=false
Value of attribute leg_mpath_enable set successfully
# scsimgr get_attr –D /dev/rdisk/disk17 –a leg_mpath_enable
SCSI ATTRIBUTES FOR LUN : /dev/rdisk/disk17
name = leg_mpath_enable
current = false
default = true
saved =
2. Clear the statistics, as follows:
# scsimgr clear_stat -D /dev/rdisk/disk17 all_lpt
scsimgr: Cleared statistics successfully
# scsimgr get_stat –D /dev/rdisk/disk17 all_lpt | grep "Total I/Os processed"
Total I/Os processed = 0
Total I/Os processed = 0
Total I/Os processed = 0
Total I/Os processed = 0
3.
Transfer data through /dev/rdsk/c5t2d4, as follows:
# dd if=/dev/rdsk/c5t2d4 of=/dev/null count=120
120+0 records in
120+0 records out
# scsimgr get_stat -D /dev/rdisk/disk17 all_lpt | grep "Total I/Os processed"
Total I/Os processed = 130
Total I/Os processed = 0
Total I/Os processed = 0
Total I/Os processed = 0
I/O transfers are performed only on the lunpath corresponding to /dev/rdsk/c5t2d4.
If the corresponding lunpath is not available and leg_mpath_enable is set to false,
/dev/rdsk/c5t2d4 cannot be opened. In the following example, multi-pathing is disabled for
disk17 and the cable to HBA 0/2/1/0 is disconnected.
# scsimgr get_attr –D /dev/rdisk/disk17 –a leg_mpath_enable
SCSI ATTRIBUTES FOR LUN : /dev/rdisk/disk17
name = leg_mpath_enable
current = false
default = true
saved =
# ioscan -kfnNC lunpath