Extent Striping using LVM

[Santosh_16]

Hi,

Please provide with solution on this.

I have 12 Luns each in different Array Group on XP attached to 4 FC Controller

I want to create a New VG with extent based striping.

Please let me know the steps involved to achieve the best I/O Performance.

TIA,
Santosh

[Michael Tully]

Well you could stripe everything, all LUN's being in the same volume group depending on the size of course of the LUN's. Also use 'scsictl' to increase the queue depth. Have a look at the man page.

# lvcreate -n -i 12 -I 64 -l 2048 /dev/myvg
# scsictl -m queue_depth=16 /dev/rdsk/cXtYdZ (for each LUN)

[Slawomir Gora]

Hi,

create vg group

vgcreate -g grp_test /dev/vgtest /dev/dsk/....

create lv

lvcreate -D y -s g -r N -L 1000 -n lvtest1 /dev/vgtest

scsictl -m queue_depth=16 /dev/rdsk/cXtYdZ (for each LUN)

[Tim D Fulford]

Once you have created ypur volumegroup, say vgxx, create an lvmpvg file. vi /etc/lvmpvg
VG vgxx
PVG primary
/dev/dsk/c0t0d0
/dev/dsk/c1t0d0
/dev/dsk/c2t0d0
/dev/dsk/c3t0d0
/dev/dsk/c0t0d1
/dev/dsk/c1t0d1
/dev/dsk/c2t0d1
/dev/dsk/c3t0d1
/dev/dsk/c0t0d2
/dev/dsk/c1t0d2
/dev/dsk/c2t0d2
/dev/dsk/c3t0d2

If you have alternate links to the disks then create an additional PVG called say "alternate". Note that I've evenly loaded the 4 controllers. I suggest you round robbin the controlelrs such that you will get as even as possible usage over the controllers.

2 - Create the LV's
lvcreate -D y -s g -n -L vgxx

3 - You might want to turn off bad-block re-allocation (see lvchange, I don't remember the exact command, but I think it is lvchange -r N /dev/vgxx/)

Tim