Auto Image Replication (AIR): How To move a copy of an image back to the source master server

Auto Image Replication (AIR): How To move a copy of an image back to the source master server

Article: 100009391
Last Published: 2014-05-28
Ratings: 7 2
Product(s): NetBackup

Problem

Auto Image Replication (AIR) is often used to keep copies for a longer retention period in a master server domain that is different from the master server that originally created the backup image.  If a client has a backup image that has expired in it's local master server's catalog, you may be able to replicate a remote copy back to the source master server domain by reversing the replication process (reverse AIR). From the original master server, you can find remote images which are still available for recovery (haven't expired yet) using the nbstlutil command line in the source domain:

nbstlutil repllist

This command will list all of the images that have been replicated to target master servers.  You can use additional command line options to filter the results.

Solution

For the example below the image we wish to replicate is 'client1_1367860165'. We have 2 master servers: "MasterA" the original master server which no longer contains the image, and "MasterB" a second Master server which still contains the image. Images were originally replicated using the SLP definition above (Air2PD).

Note:

  • NetBackup will not auto-import any backup ID that remains in its catalog. This includes:
    • images whose copies are all expired but not yet cleaned up
    • images where a replication copy still exists (use nbstlutil repllist to see these).  

      If any copies remain you will need to expire all copies on MasterA and run image cleanup. You will also need to eliminate the replication copy record reported by nbstlutil repllist.
       
  • You need an import SLP on MasterA that targets the relevant PureDisk Disk Pool Storage Unit. If you do not already have one, this will need to be created (see TECH189382 in Related Articles below). 

Solution steps:

  1. Choose the Disk Pool on MasterB that will replicate the image to MasterA, and make a note of the Storage Server it uses. If a suitable Disk Pool does not already exist, use the standard method to create one (see TECH189382 in Related Articles below). 
    (To confirm you have AIR setup to replicate in both directions, check the diskpool has entries for both Source and Target in the Replication field; or use the command: nbdevquery -listdp -stype PureDisk -U to confirm that disk pool has all 3 Flags: ReplicationSourceReplicationTarget, and TargetedReplication.)
  2. Search MasterB's catalog for the backup image. If the required image on MasterB is not already stored on the Disk Pool from Step 1, use bpduplicate or the catalog GUI to place a copy there.
  3. Remove any record of this backup id in MasterA's catalog and database.  Expire any local copies using:

    MasterA prompt> bpexpdate -backupid client1_1367860165 -d 0 -force

    Note: this requires the image be Storage Lifecycle State 'complete'. If you get the following error:

    EXIT STATUS 1573: Backup image cannot be expired because its SLP processing is not yet complete

    ...you will need cancel the image in SLP using the command:

    MasterA prompt> nbstlutil cancel -backupid client1_1367860165
    MasterA prompt> bpexpdate -backupid client1_1367860165 -d 0 -force


    Note: if you later get EXIT STATUS 1573, the commands above can be used but they will delete the auto-import event, so you will have to replicate the image again.
     
  4. Replicate the image from MasterB to MasterA:

    MasterB prompt> nbreplicate -backupid client1_1367860165 -cn <local copy number> -rcn <copy number plus 101> -target_sts <target storage server from step1> -slp_name reverse-air -target_user <target storage server username> -target_pwd <target storage server password>

    At this point you should see a replication job start on MasterB.  Shortly after the replication job is finished, the target storage server should notify MasterA that the image is available for import.  You can confirm this by running:

    MasterA prompt> nbstlutil pendimplist

    ...and searching for the backup id you are interested in.  After some time, depending upon the size of your import backlog (the number of images returned by the previous command), this image should be batched in an import job.  

Don't forget this last step:
The image is will be imported and set to lifecycle complete with the same expiration date that the source copy had. You may want to manually change the expiration date/time using bpexpdate (for usage see the command guide in Related Articles below).


Applies To

This solution works only for NetBackup 7.5.0.5 and above.

This solution is only supported for Veritas's PureDisk storage type.  In addition, replication from NetBackup PDDO or a NetBackup 5020 appliance to a NetBackup Media Server Deduplication Pool (MSDP) is explicitly NOT SUPPORTED.  If you are using MSDP to PDDO replication, you may still perform this procedure, however, if you have a PDDO device in the source master server domain that you can replicate back to.

The ability to reverse the image replication process is not a part of the qualification program for third party storage devices to be qualified for NetBackup AIR. This means the functionality described here has not been tested with third party storage devices and is therefore explicitly NOT SUPPORTED for third party (non-Veritas) storage devices.

The following figure shows an example Storage Lifecycle Policy in the original master server domain:
Example SLP definition

In this example, any backup image that is older than 2 weeks, but less than 1 year old, may need to be recovered from the target master server.

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