How to achieve over 2 TB/hr network backup with Integrity entry-class servers running HP-UX 11i v3

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To verify the setting of the lunpath for the next use of the tape device /dev/rtape/tape12_BEST,
reissue the scsimgr get_attr command as used in the first example of this section. This displays
the lpt_lockdown and lpt_to_lockdown attributes for the device, as in the following example:
#
# scsimgr get_attr -D /dev/rtape/tape12_BEST -a lpt_lockdown -a lpt_to_lockdown
SCSI ATTRIBUTES FOR LUN : /dev/rtape/tape12_BEST
name = lpt_lockdown
current = 0/7/0/0/0/1.0x500110a0008b9f73.0x0
default =
saved =
name = lpt_to_lockdown
current = 0/7/0/0/0/1.0x500110a0008b9f73.0x0
default =
saved = 0/7/0/0/0/1.0x500110a0008b9f73.0x0
#
Note
The tunable lpt_to_lockdown device attribute is now set to the designated lunpath hardware
path specified with the scsimgr save_attr command.
Using Persistent DSFs
One of the invaluable features of HP-UX 11i v3 is the availability of Persistent DSFs, which are bound
by using the LUN WWID of the storage device. When any SAN changes are made, the Persistent
DSFs remain unchanged and valid for device access. During testing, a check was made to see
whether swapping the two dual 4Gb FC HBAs for two other FC HBAs in different I/O slots would
cause an issue. With the swapping of the HBAs and re-connection of the FC links, an ioscan
showed that the tape devices had retained their original Persistent DSFs. Thus, no configuration
changes were required on the system or on the backup utilities accessing the tape devices.
Controlling interrupts (intctl)
The intctl command allows you to display and modify interrupt assignments for the CPUs in the
system. As part of this characterization effort, intctl was used to determine whether manual
changes of interrupt assignments could optimize backup I/O throughput on the backup server. In
addition to testing with the default interrupt assignment, the intctl command was used to evaluate
two additional interrupt handling strategies:
• Spread evenly across all CPUs the interrupts of the 1GbE ports and FC ports in use for the
backup
• Collocate interrupts for the1GbE ports and the FC port associated with a tape device on the
same CPU
Test results on the rx3600 and rx6600 servers revealed minor differences between the interrupt
handling strategies in overall backup I/O throughput for these systems. The differences were not
significant enough to recommend any changes. In fact, the default interrupt configuration allocation
was frequently the best strategy for the many backup operations performed with this characterization
effort. However, although changing the interrupt-handling configuration did not show benefit with the
entry-level backup server test characterization, it may have a positive effect for other workload types
or with larger server configurations.