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

tape devices by using scsimgr save_attr or scsimgr set_attr to manually set the tunable

lpt_to_lockdown attribute to the desired lunpath to use for accessing the tape device. The

settable lpt_to_lockdown attribute for tuning tape device access was introduced in HP-UX 11i v3

update 4 (Fusion 0903). The scsimgr get_attr command displays the current load balancing

policy in effect and the associated I/O path that is locked down for a particular tape device.

The scsimgr get_attr command is also very useful for displaying the tape device’s LUN WWID

and configured LUN ID for correlation of the associated tape device within the tape library. Most

tape library management tools display tape device WWIDs and the actual physical location of the

tape device within the tape library.

In the following examples, the scsimgr command displays and alters the current load balancing

settings, which for tape devices is the lunpath locked down for I/O access to the serial tape device.

In the first example that follows, the scsimgr get_attr command displays both the default read-

only lpt_lockdown and the settable lpt_to_lockdown device attributes. This informs you of the

current and saved settings used for accessing the tape device represented by the DSF

/dev/rtape/tape12_BEST:

# 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 = 0/3/0/0/0/1.0x500110a0008b9f72.0x0

default =

saved =

name = lpt_to_lockdown

current =

default =

saved =

Note that in the preceding output the tunable lpt_to_lockdown has no value. This means it has not

been set, and so the default lpt_lockdown load balancing algorithm is in effect. When the tape

device is next opened, a lunpath on a FC port with the least I/O load will be allocated by default for

access to the tape device. The path currently being used or, if the device is not currently opened,

that was last used, is shown as the current setting for the read-only lpt_lockdown device attribute.

If you want to override the default lpt_lockdown lunpath allocation, you can set the tunable device

attribute lpt_to_lockdown to the lunpath hardware path for the tape device that you prefer to use

for I/O access. It is easiest to display the lunpath hardware paths for the tape device by using the

ioscan –m lun command, and then copy the lunpath hardware path of the preferred device and

paste it in the scsimgr command line.

Use the following command to set and save across reboots the lunpath hardware path

/7/0/0/0/1.0x500110a0008b9f73.0x0 for I/O to the tape device

/dev/rtape/tape12_BEST:

# scsimgr save_attr -D /dev/rtape/tape12_BEST

–a lpt_to_lockdown=0/7/0/0/0/1.0x500110a0008b9f73.0x0

Value of attribute lpt_to_lockdown saved successfully