create new lvol in mirror env

[Fauziah Mahdan]

Hi all,
Need to confirm the step below to create new lvol in mirror disk env.
1) lvcreate -n lvolx /dev/vg00/lvolx
2) lvextend -L xxxx /dev/vg00/lvolx
3) newfs -F vxfs /dev/vg00/rlvolx
mount the dir
add in fstab
/dev/vg00/lvolx /u0x vxfs delaylog 0 2

FYI it was itanium RX4640 server

[Patrick Wallek]

In your steps, you never mirror the LV.

1) lvcreate -L -n lvolx -m 1 /dev/vg00 /dev/dsk/c?t?d?s? /dev/dsk/c?t?d?s?

2) newfs

3) mount

4) add to /etc/fstab

[Fauziah Mahdan]

Patrick I am confuse which disk will be in the cxtxdxsx and the cxtxdx?

Pls see below ioscan result for the disk
target 3 0/1/1/0.0 tgt CLAIMED DEVICE
disk 1 0/1/1/0.0.0 sdisk CLAIMED DEVICE HP 73.4GST373454LC
/dev/dsk/c2t0d0 /dev/rdsk/c2t0d0
/dev/dsk/c2t0d0s1 /dev/rdsk/c2t0d0s1
/dev/dsk/c2t0d0s2 /dev/rdsk/c2t0d0s2
/dev/dsk/c2t0d0s3 /dev/rdsk/c2t0d0s3
target 4 0/1/1/0.1 tgt CLAIMED DEVICE
disk 2 0/1/1/0.1.0 sdisk CLAIMED DEVICE HP 73.4GST373454LC
/dev/dsk/c2t1d0 /dev/rdsk/c2t1d0
/dev/dsk/c2t1d0s1 /dev/rdsk/c2t1d0s1
/dev/dsk/c2t1d0s2 /dev/rdsk/c2t1d0s2
/dev/dsk/c2t1d0s3 /dev/rdsk/c2t1d0s3

[Fauziah Mahdan]

from the HP work sheet.
it mirrored my vg00 to alternate disk 0/1/1/0.0.0

Does it means the disk1 is the alt disk c2t0d0s?

so the command should be
lvcreate -L 2000 -n /lvol11 -m 1 /dev/vg00 /dev/dsk/c0t1d0sX /dev/dsk/c0t0d0s?

s value is what 4 is it?

[Fauziah Mahdan]

sorry,
too early to reply
from vgdislay
--- Physical volumes ---
PV Name /dev/dsk/c2t1d0s2
PV Status available
Total PE 4318
Free PE 1031
Autoswitch On

PV Name /dev/dsk/c2t0d0s2
PV Status available
Total PE 4318
Free PE 1031
Autoswitch On

so the command will be
1) lvcreate -L 2000 -n lvol11 -m /dev/vg00 /dev/dsk/c0t1d0s2 /dev/dsk/c0t0d0s2
2) newfs -F vxfs /dev/vg00/rlvol11
3) mount /dev/vg00/lvol11 /u03
4) add in /etc/fstab
/dev/vg00/lvol11 /u03 vxfs delaylog 0 2


Pls confirm :-)

[SANTOSH S. MHASKAR]

Hi,

If u have 2 disks in vg00 look at the o/p
of

# strings /etc/lvmtab

it shows all the disks in vg00
eg.

#strings /etc/lvmtab
/dev/vg00
/dev/dsk/c0t6d0s2
/dev/dsk/c4t6d0s2

then to create a mirrored lv and file system on it

1) lvcreate -L 2000 -n lvol11 -m /dev/vg00 /dev/dsk/c0t6d0s2 /dev/dsk/c4t6d0s2
2) newfs -F vxfs /dev/vg00/rlvol11
3) mount /dev/vg00/lvol11 /u03
4) add in /etc/fstab
/dev/vg00/lvol11 /u03 vxfs delaylog 0 2
5) vgcfgbackup /dev/vg00

Also don't forget to add options for filesystem creation
in step 2 (if u want support for largefiles etc.) and make sure all the disks in
vg00 are bootable.

# lvlnboot -v

[Thomas J. Harrold]

Hello, if you only have two disk in your volume group, LVM is smart enough to place extents fro m each of the mirrors on different disks.

If you had 3 (or more) disks in your VG, you would consider specifying which physical disk to use (from vgdisplay -v output), but in this case you do not have to.

Simply create your new LV with the "-m 1" option, and you'll be good to go.

You can verify with "lvdisplay -v" and "pvdisplay -v" commands.

-tjh

[MHudec]

1.) lvcreate -n lvolx vg00
- this will create dummy logical volume named /dev/vg00/lvolx with 0 extents (you will later decide on which physical volume will this logical volume exist

2.) lvextend -l xxx /dev/vg00/lvolx /dev/dsk/cxtxdxs2
- xxx is number of logical extents (for example you want to have 400M logical volume and you have physical extents of 4MB size, you will need 100 logical extents - 4*100 = 400), /dev/dsk/cxtxdxs2 is the the physical volume where original extents will exist, s2 is that as you say, it is itanium system (rx*)

3.) lvextend -m 1 /dev/vg00/lvolx /dev/dsk/cytxdxs2
- this will mirror the logical volume to another, mirror, physical volume cytxdx

4.) newfs -F vxfs -o options /dev/vg00/rlvolx
- this will create vxfs filesystem on our logical volume, check -o for options like largefiles etc.

5. fstab entry etc.

Notes:
- please use -l instead of -L while defining capacity of logical volume, -l uses extents, while -L uses megabytes (and thus rounding the number of extents)
- in case you want to do this on parisc systems, physical volumes will be just cxtxdx and not cxtxdxs2 (s2 is hp-ux partition on itanium disk layout, s1 is efi partition and s3 is service partition)

[Fauziah Mahdan]

Thanks all for the reply
Ok next question
--- Physical volumes ---
PV Name /dev/dsk/c2t1d0s2
PV Status available
Total PE 4318
Free PE 406
Autoswitch On

PV Name /dev/dsk/c2t0d0s2
PV Status available
Total PE 4318
Free PE 406
Autoswitch On


/dev/vg00/lvol10 30720000 20130910 9927311 67% /u02


I need to reduce this /u02 into 15GB and this is the mirror disk too.
Is the step simple as :
backup the /u02

# umount /u02
# lvreduce -L 100 /dev/vg00/lvol10
Warning: The Logical Volume has a file system larger than the reduced size.Reducing the Logical Volume will cause filesystem corruption.
When a logical volume is reduced useful data might get lost; do you really want the command to proceed (y/n) : y
Logical volume "/dev/vg00/lvol10" has been successfully reduced.
Volume Group configuration for /dev/vg00 has been saved in /etc/lvmconf/vg.conf

# mount /dev/vg00/lvol10 /u02
vxfs mount: /dev/vg/lvol10 is corrupted. needs checking

# newfs â F vxfs /dev/vg00/rlvol10
# mount /dev/vg00/lvol10 /u02
==> Restore the backup