This article provides the brief introduction about the Networker automated group cloning operation.

Networker Automated Cloning Feature.

Cloning is a feature of the EMC NetWorker software which introduced after version 8.1 that allows for secure offsite storage and the transfer of data from one location to another. It provides the ability to create a copy of a save set from one volume to another volume. Using Clone feature, the multiple clone copies can be created so that a backup can be protected against corruption, local damage, site disaster, or loss. Cloning also provides a mechanism that can be used to move data from one storage type to another. For example, for offsite storage you can move data from disk to tape.

Automated cloning is linked with a backup group. With automated group cloning, save sets can either be automatically cloned when the group is completely backed up or immediately (immediate cloning) after each save set in the group is backed up.To configuring auto-clone

1. In the NetWorker Administration window, select Configuration.
2. Create a Group resource and then select Properties.
3. Specify the Clones option.
4. Select a value from the Clone mode attribute.

The following is the steps about how does the Group Cloning operates with either the “on save set completion” option and the “on group completion” option.

Start on save set completion (DD Boost device only)

Select Start on save set completion to start a save set clone operation each save set is backed up. If this option is selected, the NetWorker server parallelism attribute must be set to a value of 2 or higher. To access the server parallelism attribute, right-click the NetWorker server name in the left pane of the Administration window, select Properties and then select the Setup tab. This option is supported only when performing clone-controlled replication with DD Boost devices.

Networker performs the following steps to complete the” Start on save set completion” operation:

1. Clone job is created at the very beginning of the save group (policy) running.
2. A temp was created as the cloning source file as well. By default, the path is “\\nsr\\tmp\\sg\\ \\<.groupName>”
3. The nsrclone command was started with the following parameters : nsrclone -s bdi-prd-nwk.corp.danamon.co.id -v -D 5 -b ddboost_sql_bsd_clone -C 1 -i "D:\\Program Files\\EMC NetWorker\\nsr\\tmp\\sg\\PRD-Adhoc-SQL-Cumulative\\.PRD-Adhoc-SQL-Cumulative" -g PRD-Adhoc-SQL-Cumulative
4. Every time a save job complete, it will writes the SSID into the file \\nsr\\tmp\\sg\\ \\<.groupName>.  nsrclone job periodically checks on this file to get the cloning source.
5. The temp file will be deleted after the save group (workflow) completed

Thus, to ensure the cloning accuracy, we need to make sure the above file do not exist before the group started, and the file is deleted after the group completed. We can also manually open the files to check if there are questions about the save sets need to be cloned.

Start on Group Completion

Select Start on group completion to start clone operations only after all savesets in the group are backed up.

Networker performs the following steps to complete the ” Start on Group Completion” operation:

1. Clone job is only created after all save jobs complete.
2. Before the nsrclone binary started, Networker server queries media database to determine the save sets need to be cloned.
3. The Media database queries includes the criteria that  “save set start time” >= “save group start time”, to ensure only the most recent backup are being cloned.
4. After the query returned, the SSID was passed directly the nsrclone binary, as shown below: nsrclone -s bdi-prd-nwk.corp.danamon.co.id -v -D 5 -b ddboost_sql_bsd_clone -C 1 -S -f < 497909124 514686338

We should understand that “save set start time” is from the client, but the “save group start time” from Networker server. Thus, if there are time difference between server and client, save set might be missing while doing the group cloning. The following screen shot is an example while only the index save set are being cloned. If we enabled NSRD to D5 or higher, we will be able to see the media database query.

Author: Fenglin Li

iEMC APJ

Please click here for for all contents shared by us.