A rare potential for data loss exists where the upgrade process of a clustered UNIX or Linux Server from 5.x to 6.x can result in the Enterprise Media Manager (EMM) database being created locally on the cluster node, rather than on the shared disk.

Article:TECH54729  |  Created: 2008-01-19  |  Updated: 2008-01-19  |  Article URL http://www.symantec.com/docs/TECH54729
Article Type
Technical Solution

Product(s)

Environment

Issue



A rare potential for data loss exists where the upgrade process of a clustered UNIX or Linux Server from 5.x to 6.x can result in the Enterprise Media Manager (EMM) database being created locally on the cluster node, rather than on the shared disk.

Solution



Introduction:
When updating a clustered 5.x Server to NetBackup 6.x that will be the EMM Server, an issue with the cluster_upgrade script may cause the EMM database to become local, not shared, in specific configurations (described below in the How to Determine section).  

When the issue occurs, the upgrade will appear to complete normally on all nodes, but the upgrade process will have failed to identify the server as a clustered EMM server.  This will result in a configuration with a local copy of the EMM database on a single node, rather than a copy which is shared across all nodes.  In this circumstance, the possibility of data loss exists due to the discrepancy between the local copy of EMM and the non-EMM catalog components on the shared disk.


NetBackup Upgrade Portal:
It is important to refer to the upgrade portals for NetBackup 6.0 and 6.5 for key information and instructions on upgrading NetBackup.  The upgrade portal contains several documents which detail the requirements, upgrade steps and other information needed for a successful upgrade.  The portals are linked in the related documents section below.


What is Affected:
The following version(s) of NetBackup are affected by this issue, on all supported UNIX and Linux Cluster platforms:
NetBackup Server / Enterprise Server 6.0 GA
NetBackup Server / Enterprise Server 6.0 MP4 (Full CD install/upgrade)
NetBackup Server / Enterprise Server 6.5
Note: This issue only affects upgrades from 5.x to full versions of NetBackup 6.x. Therefore, 6.0 MP4 is only affected when upgrading to 6.0 MP4 as a full version via CD-ROM, rather than applying the MP4 patch available from the Support site.

How to Determine if Affected:
To be affected by this issue, the following 3 conditions must be met:
1. The NetBackup 5.x Global Device Database host, also known as GlobDB (exists by default on the Master Server) is a clustered UNIX or Linux server.
2.  Either of the following are true:
A.  The command "/usr/openv/volmgr/bin/tpautoconf -get_gdbhost" returns a fully qualified name.
or
B.  The value of VNAME in the file /usr/openv/netbackup/bin/cluster/<cluster_type>/<cluster_type>_NBU_RSP is a fully qualified name, the short form of which matches the short form of the name returned in 2A (above).
3.  The server is then upgraded to NetBackup 6.x

After the upgrade, the following can be done to check if an EMM cluster is affected.  
1.  View the contents of /usr/openv/netbackup/bp.conf
2.  Observe the VXDBMS_NB_DATA parameter.  If it is not set to a shared disk path, such as <shared_disk>/db/data, the server is affected.  In this circumstance, it is recommended to contact Symantec Technical Services.


Formal Resolution:
Preventative (prior to upgrading)
This issue is resolved in the following NetBackup patches, which can be found below, in the Related Documents section:
-  Independent Patch 6.5I1
-  Independent Patch 6.0I1

As this issue occurs during the actual upgrade process, a resolution is not available in the form of a direct install.  Instead, a replacement cluster_upgrade script (provided in the patch above) is available to allow the upgrade to take place successfully.  However, this script must be used during the upgrade process.  

Recovery
If the upgrade has already been performed and the EMM server cluster is affected, please contact Symantec Enterprise Technical Services so that the state of the configuration can be analyzed.  If affected by this issue, the EMM Database is not shared and is therefore subject to being inconsistent with other NetBackup databases.  This condition can lead to data loss and should be investigated immediately.


Best Practices:
Symantec strongly recommends the following best practices:
1. Always perform a Full backup prior to and after any changes to your environment.
2. Always make sure that your environment is running the latest version and patch level.


How to Subscribe to Software Alerts:
If you have not received this TechNote from the Symantec Email Notification Service as a Software Alert, please subscribe at the following link:
 http://maillist.entsupport.symantec.com/subscribe.asp



Legacy ID



293034


Article URL http://www.symantec.com/docs/TECH54729


Terms of use for this information are found in Legal Notices