Installing and using HP-UX advanced path
failover drivers
Advanced path failover for HP-UX is implemented by updating HP-UX drivers to support advanced path
failover with the LTO-6 tape drives. The drivers function as both failover and non-failover drivers.
The updated drivers are:
• HP-UX tape driver (estape) — used for data path failover
• HP-UX media changer driver (eschgr) — used for control path failover
• HP-UX SCSI stack driver (esctl) — used for data path and control path failover
During the device open, the device driver checks to see whether the device is capable and enabled for
advanced path failover. If so, the device driver opens a failover session and continues with further device
operations. Otherwise, the driver uses the non-failover driver code. Note that until the device is opened
for the first time, the drivers do not know whether the device is capable of advanced path failover or not.
HP-UX 11i v3 performs automatic load balancing and will open new tape drive connections using the best
available path to spread the load across all available paths. In HP-UX 11i v3, the default load balance
policy for tape drives and libraries is the “Path-lockdown” policy. With this policy, the host determines a
path for sending I/O requests to the device when the device is opened for the first time and this path
remains fixed. Without the advanced path failover feature installed, if this path fails, a new path is only
chosen when the device is next opened. With the advanced path failover feature, the best path will be
chosen as the lockdown path. If this path fails, the driver will automatically fail over to the next available
best path, which becomes the new lockdown path for all further I/O requests.
For additional information see the following man pages: scsimgr(1M), ioscan(1M), mknod(2), mksf(1M),
rmsf(1M).
Installing advanced path failover drivers
HP-UX patches are available at
https://h20566.www2.hp.com/portal/site/hpsc/patch/home/
. To locate
the patches, search for
estape
,
eschgr
, and
esctl
, or the patch number and then look at the
Prepby
field to see if there is a superseding patch.
To install the advanced path failover drivers, use the standard HP-UX kernel patch installation process to
install the following patches on the HP-UX host servers running HP-UX 11i v3:
Procedure
1.
HP-UX Tape driver patch (estape) - PHKL_43680 or superseding patch
2.
HP-UX Media changer driver patch (eschgr) - PHKL_43681 or superseding patch
3.
HP-UX SCSI stack (Mass storage stack) driver patch (esctl) – PHKL_43819 or superseding patch
The server will automatically reboot as part of the installation process.
Installing and using HP-UX advanced path failover drivers
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