HPVM PV MOVE

[Misbah Elalami]

Thanks alot Chandra - I get a chance to try that out next week - and will let you know how it goes - THANKS A MILLION for all the help and the very specific instructions... I was a little worried about using DD because I wasn't sure what it would do to the underlying LVM structures - but I think it will be okay... will let you know how it all goes - thanks Alot again ...

[chris huys_4]

Hi,

I would mirror the volumes, to the new san luns.

Mirroring will keep the striping intact, so I dont see a problem there.

When everything is mirrored, shutdown the virtual machine, "disconnect" the "old san luns" from the vm guests, reduce the "old san luns" from the "vmguest volumegroups" on the vmhost, "connect" the "new san luns to the vm guest" and start up the vmguests.

Much better, then using, something antiquate ;), like dd, with a volumemanager.

NOTE : the whole point of introducing volumemanagers, more then 14+ years ago, on hp-ux, was not to need to use raw disk devices and dd, ever again. (until oracle came up with asm offcourse ;) sorry couldnt resist) )

NOTE2: And oh yes, you would have had problems with "the dd from the old san luns to new san luns", sooner or later, as the new san luns, dont have the exact same size as the old san luns.

Greetz,
Chris

[Dave Johnson_1]

@Chris,
You missed the statement in his original post stating the lvols are striped. There is no version of HP-UX or add-on that allows striping and mirroring.

[Misbah Elalami]

So a quick question comes up then before I start after reading the comment from Chris

"NOTE2: And oh yes, you would have had problems with "the dd from the old san luns to new san luns", sooner or later, as the new san luns, dont have the exact same size as the old san luns."

My new SAN drives are bigger than than the existing old SAN drives by a a few PP's or so - does DD require exact same size - or if the new disk is larger - should that work as well?

Thanks for clarifying all

[chris huys_4]

> My new SAN drives are bigger than than
> the existing old SAN drives by a a few
> PP's or so - does DD require exact same
> size
dd from a smaller to a bigger disk will work, initially, but like all "workaround methods", a normal pvcreate of the "bigger disk" would have contained at least a lvm extent more "in its lvm header" then "the amount of extents the lvm header, that comes through the dd of the smaller disk contains" and thus, this can be the source of problems in the future...

So if, the dd would need to be done, which it not needed in this case, only equal sizes of disks, would limit the amount of problems, imo..

[chris huys_4]

> @Chris,
> You missed the statement in his original
> post stating the lvols are striped. There
> is no version of HP-UX or add-on that
> allows striping and mirroring.

Thats dependent on what is understand beneath striping.

If its extent based striping, then mirroring is certainly possible..

i.e.
ronin # lvdisplay -v /dev/vgmirrorstriping/lvol1
--- Logical volumes ---
LV Name /dev/vgmirrorstriping/lvol1
VG Name /dev/vgmirrorstriping
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule striped
LV Size (Mbytes) 40
Current LE 10
Allocated PE 20
Stripes 2
Stripe Size (Kbytes) 8
Bad block on
Allocation strict
IO Timeout (Seconds) default

--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/disk/disk70 5 5
/dev/disk/disk72 5 5
/dev/disk/disk74 5 5
/dev/disk/disk75 5 5

--- Logical extents ---
LE PV1 PE1 Status 1 PV2 PE2 Status 2
00000 /dev/disk/disk70 00000 current /dev/disk/disk74 00000 current
00001 /dev/disk/disk72 00000 current /dev/disk/disk75 00000 current


Greetz,
Chris

[chris huys_4]

> @Chris,
> You missed the statement in his original
> post stating the lvols are striped. There > is no version of HP-UX or add-on that
> allows striping and mirroring.
Just to be clear. "standard" Striping + mirroring does work as my example shows.. but I did it on a hp-ux 11.31 system.

So upgrading first the vmhost to hp-ux 11.31 would solve that problem. ;)

So yes, if its the normal "striping" and its hp-ux 11.23 and upgrading the vmhost to hp-ux 11.31 is no option, then indeed, daves solution is probably the one I would also use. (i.e. creating a new vg with the new san luns and filesystem copying the data over ..)

Greetz,
Chris

[sujit kumar singh]

theres a pactyh for 11.23 to enable 16TB support+ mirror stripes, can have that installed on the systems

s700_800 11.23 LVM Striped/Mirror + 16TB LV Enablement PHCO_37939
posted: 2008/08/21
PHCO_37939
posted: 2008/08/21


regards
sujit