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

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# scsimgr set_attr -D /dev/rdisk/disk17 –a ping_recovery=count_based -a
ping_count_threshold=20
Value of attribute ping_recovery set successfully
Value of attribute ping_count_threshold set successfully
Setting a time-based deferred path recovery policy
The following example shows how to consider failed lunpaths of disk17 to be back online only if
pings continually succeed for 10 seconds. The ping_type attribute is already set to basic or
extended for disk17.
# scsimgr set_attr -D /dev/rdisk/disk17 –a ping_recovery=time_based -a
ping_time_threshold=10
Value of attribute ping_recovery set successfully
Value of attribute ping_time_threshold set successfully
Native multi-pathing: A concrete example
In this section, a target port is disconnected and reconnected while I/O operations are flowing. This
example shows the following:
• Error reporting
• Asynchronous target port offline notification
• ioscan and scsimgr use cases to display multi-pathing information
• Lunpath failover
• Lunpath recovery
Initiate some I/O traffic as follows:
# dd if=/dev/rdisk/disk15 of=/dev/rdisk/disk16 &
Then, physically disconnect the target port with the world wide name
0x500508b3009097f9.
The administrator is notified via a message in /var/adm/syslog/syslog:
Jan 31 02:08:50 hpfcs835 vmunix: class : tgtpath, instance 3
Jan 31 02:08:50 hpfcs835 vmunix: Target path (class=tgtpath, instance=3) has gone offline.
The target path h/w path is 0/2/1/0.0x500508b3009097f9
Jan 31 02:08:50 hpfcs835 vmunix:
Jan 31 02:08:50 hpfcs835 vmunix: class : tgtpath, instance 6
Jan 31 02:08:50 hpfcs835 vmunix: Target path (class=tgtpath, instance=6) has gone offline.
The target path h/w path is 0/4/1/0.0x500508b3009097f9
Because the target port SAN element is involved in the definition of two target paths, both target
paths went offline.
The following ioscan command shows that two target paths have gone to
NO_HW state:
# ioscan -fnNC tgtpath
Class I H/W Path Driver S/W State H/W Type Description
…
tgtpath 7 0/2/1/0.0x500508b3009097f1 estp CLAIMED TGT_PATH
fibre_channel target served by td driver
tgtpath 3 0/2/1/0.0x500508b3009097f9 estp NO_HW TGT_PATH
fibre_channel target served by td driver
tgtpath 8 0/4/1/0.0x500508b3009097f1 estp CLAIMED TGT_PATH
fibre_channel target served by td driver
tgtpath 6 0/4/1/0.0x500508b3009097f9 estp NO_HW TGT_PATH
fibre_channel target served by td driver
Gather statistics for offline events on the target path using scsimgr, as follows:
# scsimgr get_stat -H 0/4/1/0.0x500508b3009097f9
...
Target path offline events from I/F driver = 1