Manualshelf

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

ManualsBrandsHP ManualsSoftwareHP-UX 11i v1.6 Technical Computing (TCOE) LTU
41424344454647484950
HP-UX Handbook – Rev 13.00 Page 45 (of 110)
Chapter 13 LVM
October 29, 2013
***** LVM-VG: 0557706517-0986205681
1 grcdg319:c4t1d0 0630309352-0968061502 0/12/0/0.1.0 HP/C5447A (0x02/vgsap)
grcdg319:c5t1d0 0630309352-0968061502 0/12/0/1.1.0 HP/C5447A (0x02/vgsap)
hprtdd32:c4t1d0 0630309352-0968061502 0/6/0/0.1.0 HP/C5447A (0x02/vgsap)
hprtdd32:c5t1d0 0630309352-0968061502 0/6/0/1.1.0 HP/C5447A (0x02/vgsap)
2 grcdg319:c4t0d0 0630309352-0968061503 0/12/0/0.0.0 HP/C5447A (0x02/vgsap)
grcdg319:c5t0d0 0630309352-0968061503 0/12/0/1.0.0 HP/C5447A (0x02/vgsap)
hprtdd32:c4t0d0 0630309352-0968061503 0/6/0/0.0.0 HP/C5447A (0x02/vgsap)
hprtdd32:c5t0d0 0630309352-0968061503 0/6/0/1.0.0 HP/C5447A (0x02/vgsap)
***** LVM-VG: 0630309352-1002790984
1 grcdg319:c4t2d0 0630309352-1002790983 0/12/0/0.2.0 HP/C5447A (n/a)
hprtdd32:c4t2d0 0630309352-1002790983 0/6/0/0.2.0 HP/C5447A (n/a)
In the output above you can see:
One non-shared disk in vg00 for each node.
Two shared disks, each having one alternate link in shared VG vgsap on each
node.
One shared disk without alternate link that is not part of a VG.
LVM striping
Introduction
The "striping" of Logical Volumes is a well-proven method of balancing I/O across
multiple disks and I/O interfaces. It is particularly appropriate for large intensively
accessed databases, and is often a more practicable approach to achieving good
throughput than any attempt to "manually" position file systems on specific hardware.
For some time now it has been possible to set up "Extent-based" striping quite easily -
this involves the distribution of the extents in a Logical Volume in a "round-robin"
fashion across two or more PVs. This has always been possible with LVM, but prior to
the "-D" option being made available for the "lvcreate" command, it was necessary to
use scripting to build LVs with distributed extents.
An alternative "Block" striping method (-i and -I options on lvcreate) is easy to use, but
cannot be used with Mirrordisk/UX. It is also impossible to use the "pvmove" command
with LVs created in this way, and extension of LVs can be difficult or impossible if PVs
are filled in an uneven fashion - extent distribution is much more flexible in this respect.
It is also worth noting that the Extent-based striping approach is thought by many to be