By bitter experience I have noticed that the installation of HP-UX patch PHKL_41700 causes a severe drop in backup performance (up to 2/3).
According to HP the following workaround can be used. The kernel settings enable high resolution timers support
# kctune hires_timeout_enable = 1
Document link to HP documentation for hires_timeout_enable : http://h20000.www2.hp.com/bc/docs/support/SupportManual/c02255648/c02255648.pdf
Better option is to back out PHKL_41700 if possible.
Update:
The "kctune hires_timeout_enable" workaround seems to do it's job. The official fix is located in Patch PHKL_41967 (require reboot).
