LVM mirror configuration

[Torsten.]

1) Is there any file will be created for mirrored LVM like original "/dev/vg00/lvhome"?

A: the mirror works below the LVOL level, so what you see there is unchanged

2) Data of the original LVM partition will be stored in mirrored LVM after creating mirrored LVM?

A: it will be a current copy; if you write something, the system will write to both disks

3) will both original and mirrored LVM reside in same Physical Volume or in different volumes?

A: up to you; but it should be a different disk

4) you said that mirror LVM comes to effect when original LVM fails. at this situation
how to view that original LVM has failed?

A: vgdisplay will show extends as "stale"; disk as "unavailable"



You should take some time and read about the LVM basics using the links provided earlier in this thread.

[Ganesan R]

Hi again,
1) Is there any file will be created for mirrored LVM like original "/dev/vg00/lvhome"?

No

2) Data of the original LVM partition will be stored in mirrored LVM after creating mirrored LVM?
Yes. you are right. As soon as you give the mirror command LVM starts synchronize the data with mirror

3) will both original and mirrored LVM reside in same Physical Volume or in different volumes?

That depends. If lv is strict allocated then mirror will go to another disk. If it is not strict allocated , it may reside on the same disk.

4) you said that mirror LVM comes to effect when original LVM fails. at this situation
how to view that original LVM has failed?

if you give lvdisplay -v lvname command, will give status of PE's . if one disk failed then all PE from that disk will be shown as stale instead of current.

[jaivinder]

Here are the answers:
1. The main purpose of the LVM mirroring is to make data highly available , mirroring creates copies of data on the other disk in the group. We usually create the root disk mirrors in HPUX so the in case of failure we can keep our system up and running. HP LVM is one of the best in unix systems.In HP LVM we configure the RAID 1. It is costly to configure mirroring because it only gives 50% of the total disk space.
2.To configure the LVM mirroring you require the HP Mirror UX software to be installed on the server.To configure the LVM mirroring you need to have to disk in the system.
If you are setting up root disk mirror then
you need to copy all boot are and utilities on the other disk,and after that add the disk into the VG00 and the use lvexted command and use -m and provide number of mirrors accoring to your need. Once you exted the LVs do a vgsync and you are done with this.
3. To check the LVM configuration check the vgdisplay and lvdisplay . It will show you the status of mirror.See the below output:
[root@tstmqs01:/]# lvdisplay -v /dev/vg00/lvroot |more
--- Logical volumes ---
LV Name /dev/vg00/lvroot
VG Name /dev/vg00
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 1024
Current LE 32
Allocated PE 64
Stripes 0
Stripe Size (Kbytes) 0
Bad block off
Allocation strict/contiguous
IO Timeout (Seconds) default

--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c2t1d0s2 32 32
/dev/dsk/c3t0d0s2 32 32

--- Logical extents ---
LE PV1 PE1 Status 1 PV2 PE2 Status 2
00000 /dev/dsk/c2t1d0s2 00144 current /dev/dsk/c3t0d0s2 00144 current
00001 /dev/dsk/c2t1d0s2 00145 current /dev/dsk/c3t0d0s2 00145 current
00002 /dev/dsk/c2t1d0s2 00146 current /dev/dsk/c3t0d0s2 00146 current
00003 /dev/dsk/c2t1d0s2 00147 current /dev/dsk/c3t0d0s2 00147 current
00004 /dev/dsk/c2t1d0s2 00148 current /dev/dsk/c3t0d0s2 00148 current
00005 /dev/dsk/c2t1d0s2 00149 current /dev/dsk/c3t0d0s2 00149 current
00006 /dev/dsk/c2t1d0s2 00150 current /dev/dsk/c3t0d0s2 00150 current
00007 /dev/dsk/c2t1d0s2 00151 current /dev/dsk/c3t0d0s2 00151 current
00008 /dev/dsk/c2t1d0s2 00152 current /dev/dsk/c3t0d0s2 00152 current
00009 /dev/dsk/c2t1d0s2 00153 current /dev/dsk/c3t0d0s2 00153 current
00010 /dev/dsk/c2t1d0s2 00154 current /dev/dsk/c3t0d0s2 00154 current
00011 /dev/dsk/c2t1d0s2 00155 current /dev/dsk/c3t0d0s2 00155 current
00012 /dev/dsk/c2t1d0s2 00156 current /dev/dsk/c3t0d0s2 00156 current
00013 /dev/dsk/c2t1d0s2 00157 current /dev/dsk/c3t0d0s2 00157 current
00014 /dev/dsk/c2t1d0s2 00158 current /dev/dsk/c3t0d0s2 00158 current
00015 /dev/dsk/c2t1d0s2 00159 current /dev/dsk/c3t0d0s2 00159 current
00016 /dev/dsk/c2t1d0s2 00160 current /dev/dsk/c3t0d0s2 00160 current
00017 /dev/dsk/c2t1d0s2 00161 current /dev/dsk/c3t0d0s2 00161 current
00018 /dev/dsk/c2t1d0s2 00162 current /dev/dsk/c3t0d0s2 00162 current
It is showing the status of every LE. It show the current status for a healthy LE and it will show stale in faulty LE.

[Sajjad Sahir]

Dear Senthil

in simple words,

mirroring means exact copy in second disk
if u are looking a mirror what u will see
the same concept

MirrorDisk/UX

once this software product is available in u system u can start mirroring

for doing mirroring
u can use -m option with lvcreate see above
positng after -m option u have to give
how many number of mirroing u need

for removing mirroring u can use lvreduce command

please the above posting, i believe they covered all u area, so no scope to mention the same thing again

thanks and regards

Sajjad Sahir

[senthil_kumar_1]

How to find whether Mirrordisk/UX is installed or not?

[inukoti]

hi senthil,

swlist-l product | grep -i mirror

should give the package if not its not installed.

bobby

[senthil_kumar_1]

Hi

can we not do mirroring with out MirrorDisk/UX?

Is it possible

[Bijeesh]

Hi
You can see if the MirrorDisk UX is installed or not using

#swlist | grep -i mirror
If it is not installed in your system,it is not possible to do this.

[Sajjad Sahir]

Dear Senthil

for seeing software product installed u
can use the following command

swlist -l product | grep -i mirrordisk/ux


thanks and regards

Sajjad Sahir

[Avinash20]

sENTHIL : "can we not do mirroring with out MirrorDisk/UX?"

Mirror-UX is a licensed purchasable software and does not come with the Foundation OE.
(I believe in 11iv3 it comes by default)