HP-UX HB v13.00 Ch-13 - LVM

HP-UX Handbook – Rev 13.00 Page 76 (of 110)
Chapter 13 LVM
October 29, 2013
 vgscan –B – Recover /etc/lvmtab file using both persistent and legacy DSFs.
This option can be used to migrate a volume group configured with legacy DSFs
to use corresponding persistent DSFs.
Example:
#strings /etc/lvmtab
/dev/vg00
/dev/disk/disk6_p2
/dev/disk/disk5
/dev/disk/disk4
/dev/dsk/c2t0d0
/dev/dsk/c2t1d0
/dev/dsk/c3t2d0s2
# strings /etc/lvmtab.old
/dev/vg00
/dev/disk/disk6_p2
/dev/disk/disk5
/dev/disk/disk4
Note: The example above shows lvmtab and lvmtab.old, after renaming the lvmtab in
lvmtab.old, and recreating the lvmtab with the option of vgscan “-B”. The new lvmtab
includes both types of DSFs, legacy and persistent.
Alternate Links in HP-UX 11.31
LVM supports alternate links to a device to allow continued access to the device if the
primary link fails. In previous HP-UX releases LVM’s multipathing solution increases the
data availability but does not allow multiple paths to be used simultaneously. LVM still
supports this functionality in HP-UX 11i v3, but the behaviour could be different, based
on how LVM and the mass storage stacks are configured.
With the introduction of mass storage stack’s native multipathing functionality, it is no
longer required nor recommended to configure LVM alternate links.
Listed below are the alternate link behavioral differencies that could be seen, when
compared with previous releases:
 Regardless of whether LVM alternate links are configured or not, the
massstorage stack processes the I/O operations to the device, using all available
paths. That is, LVM selects the LUN and the massstorage stack select the
lunpath to be used.
 If LVM alternate links are configured, no link switching ever happens unless the
mass storage stack’s native multipathing feature is disabled using the scsimgr
command and only legacy DSFs are used in the volume group configuration.