How to perform a one time replication of a volume to another site without adding it to a replicated volume group (RVG) data set

Article:TECH28754  |  Created: 2003-01-21  |  Updated: 2012-01-24  |  Article URL http://www.symantec.com/docs/TECH28754
Article Type
Technical Solution

Environment

Issue



How to perform a one time replication of a volume to another site without adding it to a replicated volume group (RVG) data set


Solution



A volume does not need to be part of the replicated volume group (RVG) to perform a replication between the two hosts.

It is often necessary to perform a temporary replication during the minimum window time, or when there is a need to add more volumes into a replicated data set. However,  despite the fact that a volume does not need to be part of the replicated volume group, a valid VERITAS Volume Replicator (tm) license needs to be installed.

This is the command which performs a replication without using the RVG data set:

# vradmin -g <dg-name>  [-full] syncvol <volume-name> <other-host-name>:<dg-name>:<volume-name>

Syncvol performs difference-base synchronization by default. However, to perform full synchronization, specify the -full option.

Additional Notes:

* Prior to using the above command, configure Volume Manager synchronization permissions by editing the /etc/vx/vras/.rdg file on the secondary RVG. This file must contain the name of the disk group that contains the RVG or a + sign. It is recommended that the remote disk group and remote volume names match.

* Ensure there is no I/O activity going on the volume on the primary site. The volume must not be used prior to running this command, therefore unmount the file system first before executing this command on both hosts. In this way, the data which needs to be synchronized across to the other node remains current at that point in time.

* Run the command from the primary host site.


Example:

There are two hosts, A and B.

Here is the vxprint -th output from host A:

dg vvrdg        default      default  105000   1065056229.1584.srini

dm disk01       c2t1d0s2     sliced   2487     35836640 -

v  myvol        -            ENABLED  ACTIVE   204800   SELECT    -        fsgen
pl myvol-01     myvol        ENABLED  ACTIVE   205800   CONCAT    -        RW
sd disk01-04    myvol-01     disk01   2300844  205800   0         c2t1d0   ENA

rv prvg         1            ENABLED  ACTIVE   primary  1         srlvol      
rl to_gilly     prvg         CONNECT  ACTIVE   gilly    svrdg     to_srini
v  vvrvol1      prvg         ENABLED  ACTIVE   2097152  SELECT    -        fsgen
pl vvrvol1-01   vvrvol1      ENABLED  ACTIVE   2097788  CONCAT    -        RW
sd disk01-01    vvrvol1-01   disk01   0        2097788  0         c2t1d0   ENA
pl vvrvol1-02   vvrvol1      ENABLED  ACTIVE   LOGONLY  CONCAT    -        RW
sd disk01-03    vvrvol1-02   disk01   2300000  32       LOG       c2t1d0   ENA
v  srlvol       prvg         ENABLED  ACTIVE   102400   SELECT    -        SRL
pl srlvol-01    srlvol       ENABLED  ACTIVE   102900   CONCAT    -        RW
sd disk01-02    srlvol-01    disk01   2097788  102900   0         c2t1d0   ENA


and here is the vxprint -th output from host B:

dg svrdg        default      default  105000   1065056200.1135.gilly

dm disk01       c1t9d0s2     sliced   2487     35836640 -

v  myvol        -            ENABLED  ACTIVE   204800   SELECT    -        fsgen
pl myvol-01     myvol        ENABLED  ACTIVE   205800   CONCAT    -        RW
sd disk01-04    myvol-01     disk01   2300844  205800   0         c1t9d0   ENA

rv srvg         1            ENABLED  ACTIVE   secondary 1        srlvol      
rl to_srini     srvg         CONNECT  ACTIVE   srini1   vvrdg     to_gilly
v  vvrvol1      srvg         ENABLED  ACTIVE   2097152  SELECT    -        fsgen
pl vvrvol1-01   vvrvol1      ENABLED  ACTIVE   2097788  CONCAT    -        RW
sd disk01-01    vvrvol1-01   disk01   0        2097788  0         c1t9d0   ENA
pl vvrvol1-02   vvrvol1      ENABLED  ACTIVE   LOGONLY  CONCAT    -        RW
sd disk01-03    vvrvol1-02   disk01   2300000  32       LOG       c1t9d0   ENA
v  srlvol       srvg         ENABLED  ACTIVE   102400   SELECT    -        SRL
pl srlvol-01    srlvol       ENABLED  ACTIVE   102900   CONCAT    -        RW
sd disk01-02    srlvol-01    disk01   2097788  102900   0         c1t9d0   ENA


Volume myvol exists on both hosts, though it is not part of the RVG at all. It is an independent volume.

To start the data replication between these two hosts, run the following command:

# vradmin -g <dg-name>  syncvol <volume-name> <other-host-name>:<dg-name>:<volume-name>

For example in this case, from the primary host site, host A:
# vradmin -g vvrdg syncvol myvol gilly:svrdg:myvol

The following output will be displayed as a result of this command:

vradmin: WARNING:  Volumes on remote hosts host B will be overwritten. Continue with syncvol (y/n)?
y
Message from Primary:
vxrsync: INFO: Starting differences volume synchronization to remote
vxrsync: INFO:    Source host:         10.251.56.110
vxrsync: INFO:    Destination host(s): 10.251.56.211
vxrsync: INFO:    Total volumes:       1
vxrsync: INFO:    Total size:          100.000 MB

Eps_time Dest_host       Src_vol     Dest_vol     F'shed/Tot_sz  Diff  Done
00:00:00 10.251.56.211   myvol       myvol            0M/100M      0%    0%
00:00:10 10.251.56.211   myvol       myvol           24M/100M      0%   24%
Message from Primary:
00:00:20 10.251.56.211   myvol       myvol           48M/100M      0%   48%
Message from Primary:
00:00:30 10.251.56.211   myvol       myvol           72M/100M      0%   72%
Message from Primary:
00:00:40 10.251.56.211   myvol       myvol           96M/100M      0%   97%
00:00:41 10.251.56.211   myvol       myvol          100M/100M      0%  100%
vxrsync: INFO: VxRSync operation completed.
vxrsync: INFO: Total elapsed time: 0:00:41

The volume can now be mounted on host B which will have the exact copy of the data from host A ( fsck may need to be run prior to mounting it).
 
 
Please Note: This is a one time replication/copy of a volume's contents to another volume on a different site, but will not be actively replicating the changes as it would do for Volumes in a RVG.

 


Legacy ID



263530


Article URL http://www.symantec.com/docs/TECH28754


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