VxVm - CREATING A MIRRORED VOLUME

We have a host with two disk controllers c1 & c2   and with 4 disks of equal size – c1t0d0 , c1t1d0 , c2t0d0  and  c2t1d0

Adding Disks To VxVm

Add/initiate these disks to Veritas Volume manager with following conditions

• Add them to a new disk group – mydg
• Veritas Disk Names should be disk01,disk02,disk03 & disk04
• Do not encapsulate them , We will initialize them by destroying data.
• Create a default sliced Private region of 2048 Blocks ( 1024 KB)on each disk. Rest of the disk will be used by Public region

This can be done by two way. Either by the menu utility vxdiskadm

# vxdiskadm  => Add or initialize disks

or directly by using this command four times-

# vxdiskadd cxtxdx

In Both case you have to answer some questions. It will even ask you to create our new diskgroup – mydg

When Done , List all disks by the command

# vxdisk list

DEVICE TYPE          DISK          GROUP  STATUS

……

…..

c1t0d0s2      sliced        disk01        mydg          online

c1t1d0s2      sliced        disk02        mydg          online

c2t0d0s2      sliced        disk03        mydg          online

c2t1d0s2      sliced        disk04        mydg          online

…..

….

And u can check each disk with command –

# vxdisk list c1t0d0s2

Creating Subdisks on Each Veritas Disks

On each disk we will create two subdisks. Though in our example we will use only one subdisk from each disk to create our example volume.

The command syntax -  

vxmake –g <dg-name> sd   <subdisk-name>  <disk-name>,<offset>,<lenth>

Length can be in sectors (default ) of  like  200m , 2g . Offset is specified in sectors

How to find Offset

To find Free space on disks of a particular DG

# vxdg -g  mydg free

(  Do not put much wait on the numbers… all are imaginary )

DISK         DEVICE          TAG          OFFSET    LENGTH    FLAGS

disk01       c1t0d0s2        c1t0d0          0      4189320   -

disk02       c1t1d0s2        c1t1d0          0      4189320   -

disk03       c2t0d0s2        c2t0d0          0      4189320   -

disk04       c2t1d0s2        c2t2d0          0      4189320   -

So on each disk we can use “0” as the offset to create the first subdisk .

Just showing the tasks related to first disk disk01

# vxmake –g mydg sd disk01-01 disk01,0,1500m

Check whether it is created or not

# vxprint -htr|grep disk01

SD NAME       PLEX    DISK     DISKOFFS LENGTH   [COL/]OFF   DEVICE   MODE

sd disk01-01  -       disk01   0        3072000    -          c1t0d0   ENA

Again Check free disk space

# vxdg -g mydg free

DISK         DEVICE          TAG            OFFSET     LENGTH    FLAGS

disk01       c1t0d0s2        c1t0d0          3072000   1117320   -

disk02       c1t1d0s2        c1t1d0          0         4189320   -

disk03       c2t0d0s2        c2t0d0          0         4189320   -

disk04       c2t1d0s2        c2t2d0          0         4189320   -

Notice that offset as well as Length is changed for disk01

Now we will create the second subdisk disk01-02 on disk01 using this offset info.

# vxmake -g mydg  sd disk01-02  disk01, 3072000,200m

Again Check Free space on disk01

# vxdg -g mydg free

DISK         DEVICE          TAG            OFFSET     LENGTH    FLAGS

disk01       c1t0d0s2        c1t0d0          3481600   707720   -

disk02       c1t1d0s2        c1t1d0          0         4189320   -

disk03       c2t0d0s2        c2t0d0          0         4189320   -

disk04       c2t1d0s2        c2t2d0          0         4189320   -

Check that disk01 now contains two subdisk disk01-01 and disk01-02

# vxprint –htr

DM NAME          DEVICE     TYPE       PRIVLEN   PUBLEN   STATE

SD NAME          PLEX       DISK       DISKOFFS  LENGTH   [COL/]OFF  DEVICE   MODE

…………

dm  disk01       c1t0d0     sliced     2159      8378640  -

………………..

sd  disk01-01    -          disk01     0         3072000  -          c1t0d0   ENA

sd  disk01-0     -          disk01     3072000   409600   -          c1t0d0   ENA

Create Subdisks accordingly on  disk02,disk03 and disk04.. Keep the subdisk sizes same in each disk.>

Creating Plexes

The syntax to create concatenated plex is –

vxmake –g <dg-name> plex <plex-name>  sd=<sd1,sd2,sd3….>

Whereas Syntax to create a striped plex is -

vxmake –g <dg-name> plex <plex-name>  layout=stripe stwidth=32 ncolumn=3 sd=<sd1,sd2,sd3.>

In our example we will create Concatinated plexes , Instead of Striped Plexes…

# vxmake –g mydg  plex  data-main  sd=disk01-01,disk02-01

Now we will create a Plex – datamirror only from sd – disk03-01 and then attach sd- disk04-01 to it separately just to learn . But Doing it in single step is better.

# vxmake –g mydg  plex  data-mirror  sd=disk03-01

# vxsd assoc data-mirror disk04-01

# check Plexes status by command -

# vxprint –lp

# vxprint –l data-main

Creating Mirrored Volume

First create a volume – data from the plex data-main

# vxmake –U fsgen vol data plex=data-main

Now attach the second plex as a mirror

# vxplex att data data-mirror      ( Syntax  vmolex att <Volume>  <plex> )

You can directly create the Mirrored Volume form both of the plexes-

# vxmake –U fsgen vol data plex=data-main,data-mirror

Note that Volume- data is of available size 3 GB .

Now the status of your newly created volume & plexes would be

# vxprint -htr

v  data         -            DISABLED EMPTY    61440    ROUND     -        fsgen

pl data-main    data         DISABLED EMPTY    61440    CONCAT    -        RW

pl data-mirror  data         DISABLED EMPTY    61440    CONCAT    -        RW

sd disk01-01    data-main    disk01   0       20480    0         c1t0d0   ENA

sd disk02-01    data-main    disk02   20480   40960    20480     c1t1d0   ENA

sd disk03-01    data-mirror  disk03   0       20480    0         c2t0d0   ENA

sd disk04-01    data-mirror  disk04   20480   40960    20480     c2t1d0   ENA

You can now  Initiate  the volume

# vxvol start data

 

v  data         -            ENABLED  ACTIVE   61440    ROUND     -        fsgen

pl data-main    data         ENABLED  ACTIVE   61440    CONCAT    -        RW

pl data-mirror  data         ENABLED  ACTIVE   61440    CONCAT    -        RW

sd disk01-01    data-main    disk01   0       20480    0         c1t0d0   ENA

sd disk02-01    data-main    disk02   20480   40960    20480     c1t1d0   ENA

sd disk03-01    data-mirror  disk03   0       20480    0         c2t0d0   ENA

sd disk04-01    data-mirror  disk04   20480   40960    20480     c2t1d0   ENA

Now following two devices node files are already created

/dev/vx/dsk/mydg/data

/dev/vx/rdsk/mydg/data

You can create solaris ufs filesystem on the raw device

# newfs  /dev/vx/rdsk/mydg/data

# mkdir /data

# mount /dev/vx/dsk/mydg/data  /data

Now If you want to delele this volume

First unmount the Filesystem

# umount data

Then stop the volume .

# vxvol stop data  ( data is the name of the volume )

Now delte the volume,associated pleses and subdisks recursively

# vxedit -rf rm  data             ( data is the name of the volume )

If u want to delete only the volume, nothing else

# vxedit -rm  data                ( data is the name of the volume )