Deployment KB: How to perform Linux host based migration using Veritas volume manager (VxVM).

The article covers the migration of Linux server from VNX array to PowerMax storage array.

- Create LUNs having the same size as the source array and add them to storage group
- Create initiator group having the initiators of the host
- Create port group having the front-end ports used in the zoning
- Create masking view and add to it the storage group , port group and the initiator group

From the server side:
1- Prechecks on the server:

a- Display all the disks on the server

# vxdisk -o alldgs list
Example:
[root@hostname ~]# vxdisk -o alldgs list
DEVICE                     TYPE            DISK                       GROUP        STATUS
emc_clariion0_139 auto:cdsdisk    emc_clariion0_139  DG_name online thinrclm

b-  Display all the disk groups running on the server:

# vxdg list

c- Display the volumes on the server:

 # vxprint -hrt
Example:
[root@hostname ~]#  vxprint -hrt
Disk group: DG_name
v  name_vol    -            ENABLED  ACTIVE   586647552 SELECT   -        fsgen
pl name_vol-01 name_vol    ENABLED  ACTIVE   586647552 CONCAT   -        RW
sd emc_clariion0_139-01 name_vol-01 emc_clariion0_139 0 73331168 0 emc_clariion0_139 ENA

 

 

2- Rescan the server to discover the new target devices using the commands:

# vxdisk scandisks
# /usr/bin/rescan-scsi-bus.sh

 List the devices on the server to verify that the new devices are discovered:

# vxdisk -o alldgs list
Example:
[root@hostname ~]#  vxdisk -o alldgs list
DEVICE                       TYPE                 DISK                           GROUP        STATUS
emc_clariion0_139 auto:cdsdisk    emc_clariion0_139  DG_name online thinrclm
emc0_04aa               auto:none        -                                     -               online invalid thinrclm

3- Format the new disks:

# vxdisksetup -i <disk_name> format=cdsdisk 
Example:
[root@hostname ~]# vxdisksetup -i emc0_04aa format=cdsdisk 

Verify that the disk is formatted:
Example:

[root@hostname ~]# vxdisk -o alldgs list
DEVICE                  TYPE                DISK                      GROUP        STATUS
emc_clariion0_139 auto:cdsdisk    emc_clariion0_139  DG_name online thinrclm
emc0_04aa            auto:cdsdisk      -                                  -            online thinrclm

4- Add the new disk to the disk group:

# vxdg -g <Disk group name> adddisk <disk name>

Example:
[root@hostname ~]# vxdg -g DG_name adddisk emc0_04aa

To verify:

[root@hostname ~]# vxdisk -o alldgs list
DEVICE                  TYPE                DISK                      GROUP        STATUS
emc_clariion0_139 auto:cdsdisk    emc_clariion0_139  DG_name online thinrclm
emc0_04aa            auto:cdsdisk    emc0_04aa              DG_name online thinrclm

5-  Migrate the data in the volume using vxassist command:
vxassist  creates a mirror for the plex in the volume on the new array 

# vxassist -b -g <Disk group name> mirror <volume name>  enclr:<enclosure name> name logtype=none
Example:
[root@hostname ~]# vxassist -b -g DG_name mirror name_vol enclr:emc0 logtype=none

Note: This command will create a new plex inside the volume on the new array. The plex state will be write only until all the data is copied then it's state will be RW.
Example:

[root@hostname ~]#  vxprint -hrt
v  name_vol    -            ENABLED  ACTIVE   586647552 SELECT   -        fsgen
pl name_vol-01 name_vol    ENABLED  ACTIVE   586647552 CONCAT   -        RW
sd emc_clariion0_139-01 name_vol-01 emc_clariion0_139 0 73331168 0 emc_clariion0_139 ENA
pl name_vol-02 name_vol ENABLED TEMPRMSD 586647552 CONCAT - WO
sd emc0_04aa-01 name_vol-02 emc0_04aa 0 73333440 0     emc0_04aa EN

6- Monitor the data copying using the command:

# vxtask list

7- After data copy is completed the volume will have 2 plexes in sync and the new plex state will be RW
Example:

[root@hostname ~]#  vxprint -hrt
v  name_vol    -            ENABLED  ACTIVE   586647552 SELECT   -        fsgen
pl name_vol-01 name_vol    ENABLED  ACTIVE   586647552 CONCAT   -        RW
sd emc_clariion0_139-01 name_vol-01 emc_clariion0_139 0 73331168 0 emc_clariion0_139 ENA
pl name_vol-02 name_vol    ENABLED  ACTIVE   586647552 CONCAT   -        RW
sd emc0_04aa-01 name_vol-02 emc0_04aa 0 73333440 0     emc0_04aa ENA

8- Cleanup the volume by removing the old plex:

# vxplex -g <DG name> -o rm dis <plex running on the source array>
Example:
[root@hostname ~]# vxplex -g DG_name -o rm dis name_vol-01

Verify that the plex is removed:

[root@hostname ~]#  vxprint -hrt
v  name_vol    -            ENABLED  ACTIVE   586647552 SELECT   -        fsgen
pl name_vol-02 name_vol    ENABLED  ACTIVE   586647552 CONCAT   -        RW
sd emc0_04aa-01 name_vol-02 emc0_04aa 0 73333440 0     emc0_04aa ENA

9- Reclaim the old disk:

# vxdisk reclaim <source disk name>
Example:
[root@hostname ~]#  vxdisk reclaim emc_clariion0_139

10- Remove the old disk from the disk group:

# vxdg -g <Disk group name> rmdisk <old disk name>
Example:
[root@hostname ~]#  vxdg -g  DG_name rmdisk emc_clariion0_139

To verify

[root@hostname ~]# vxdisk -o alldgs list
DEVICE                         TYPE            DISK         GROUP        STATUS
emc_clariion0_139 auto:cdsdisk    -            -            online thinrclm

11- Uninitialize the disk:

# vxdiskunsetup -C <old disk name>
Example:
[root@hostname ~]#  vxdiskunsetup -C emc_clariion0_139

Verify:

[root@hostname ~]#   vxdisk -o alldgs list
DEVICE                         TYPE            DISK         GROUP        STATUS
emc_clariion0_139 auto:none       -            -            online invalid thinrclm

From the switch side:
- Remove the zone between the old source array and the server