VG00 mirroring

[aaaA_4]

Hi,

simple question. Do I have to stop any activity on my production server during the mirroring of VG00 (MirrorDisk/UX), or is it possible to do it without any outage?

Any help appreciated.
N.

[Robert-Jan Goossens_1 · Accepted solution]

Hi,

No need to stop your apps during mirroring. You will loose some i/o performance during the mirror process.

Best regards,
Robert-Jan

[BOMBA_1]

Hi,

You don't have to stop activity during the mirroring of vg00 because the only way to stop activity on vg00 is to stop the server and if you stop the sever you can't mirror vg00.

[aaaA_4]

BOMBA,

your answer is very funny ;-) I thougt of one logical volume, with installation of Oracle software, which resides on the VG00. Anyway, thank you.

N.

[Binu_5]

Hi

Better to do in single user mode

Thanks
Binu

[Thierry Poels_1]

Hi,

you only need a reboot when initially installing the MirrorDisk/UX Software.
All the rest can be done online : mirroring, double mirroring, splitting, unmirroring.

Just note: if you mirror VG00, don't forget to make the mirror bootable (mkboot etc).

regards,
Thierry Poels.

[Bill Hassell]

Mirroring is specifically designed to occur on a running system. The initial mirroring command (lvextend -m 1) will set a flag in the driver so that the very next write (and all subsequent writes) will be mirrored. Then lvextend proceeds to sync all the extents. Mirroring is done at an atomic level, that is, at the bottom of the LVM subsystem and each write is exclusive. That means each write takes place on all the mirrors and is verified by status before proceeding. If any write fails, the extent is marked stale and access continues.

So you can mirror at anytime regardless of system activity. Note that it will keep the disks quite busy so users may notice some slowdown for a short while.

[Nguyen Anh Tien]

No need to stop you application (you have not to stop activity on your production server).
HP-MirrorDisk/UX allow you mirror lv online.
if you mirror lv on VG00. let take care for boot lv.(we call it "root disk mirroring")
Root Disk Mirroring

ï ¨ suppose that volume group vg00 contains one disk /dev/dsk/c2t2d0 and mirroring another disk /dev/dsk/c1t2d0.

# pvcreate -B /dev/rdsk/c1t2d0 (make area for LIF and boot utilities)
#vgextend /dev/vg00 /dev/dsk/c1t2d0 (extend vg00 volume)
#mkboot /dev/dsk/c1t2d0 (add boot utilities)
#mkboot -a "hpux -lq (;0) /stand/vmunix" /dev/dsk/c1t2d0 (add new hardware path)
#lvextend -m 1 /dev/vg00/lvol1 /dev/dsk/c1t2d0 (mirror)
#lvextend -m 1 /dev/vg00/lvol2 /dev/dsk/c1t2d0
#lvextend -m 1 /dev/vg00/lvol3 /dev/dsk/c1t2d0
#lvextend -m 1 /dev/vg00/lvol4 /dev/dsk/c1t2d0
#lvextend -m 1 /dev/vg00/lvol5 /dev/dsk/c1t2d0
#lvextend -m 1 /dev/vg00/lvol6 /dev/dsk/c1t2d0
#lvextend -m 1 /dev/vg00/lvol7 /dev/dsk/c1t2d0
#lvextend -m 1 /dev/vg00/lvol8 /dev/dsk/c1t2d0
#lvlnboot â r lvol1 /dev/vg00 (update BDRA of boot disk in root volume group)
#lvlnboot â s lvol2 /dev/vg00 (update BDRA of boot disk in root volume group)

#lvlnboot â v .
Boot Definitions for Volume Group /dev/vg00:
Physical Volumes belonging in Root Volume Group:
/dev/dsk/c2t2d0 (0/0/2/0.2.0) -- Boot Disk
/dev/dsk/c1t2d0 (0/0/1/1.2.0) -- Boot Disk
Boot: lvol1 on: /dev/dsk/c2t2d0
/dev/dsk/c1t2d0
Root: lvol3 on: /dev/dsk/c2t2d0
/dev/dsk/c1t2d0
Swap: lvol2 on: /dev/dsk/c2t2d0
/dev/dsk/c1t2d0
Dump: lvol2 on: /dev/d

[Eknath]

Hi,

You need not stop any application, mirroring can be done online. You may observe performance issue durin mirroring but thats only for 15-30 mins depending on data you have in vg00.

See the attachment for mirroring the vg00

locate the disk you want to mirror with the help of
#ioscan -fnC disk
#pvcreate -f -B /dev/rdsk/c_t_d_ (on new disk)
#vgextend /dev/vg00 /dev/dsk/c_t_d_
#mkboot /dev/dsk/c_t_d_
#mkboot -a "hpux -lq" /dev/dsk/c_t_d_
mirror the lvols
for i in 1 2 3 4 5 6 ...
do
lvextend -m 1 /dev/vg00/lvol$i /dev/dsk/c_t_d_
done
#cd /usr/sbin/diag/lif
#mkboot -b updatediaglif -p ISL -p HPUX -p LABEL -p AUTO /dev/rdsk/c_t_d_ (to place ODE on new disk if applicable)
#lvlnboot -b /dev/vg00/lvol1
#lvlnboot -s /dev/vg00/lvol2
#lvlnboot -r /dev/vg00/lvol3
#lvlnboot -d /dev/vg00/lvol2
#lvlnboot -v (check both thd disks are bootable)
select second boot disk path as alternate boot path.

I hope nothing is missing....

Cheers !!!
eknath





Cheers !!!
eknath

[Devender Khatana]

Hi,

Allthough it can be done online still it is suggested to be performed when system utilization is quite low. My root disk mirroring includes a complete test of mirroring i.e. trying by booting system from the alternate disk with the first one removed, allthough such a long test can be planned some time else alongwith some outage.

HTH,
Devender