NetWorker 7.6 SP4 is generally available!


It is officially on the Powerlink, NetWorker 7.6 SP4 build 1039!

Heem, you might start wondering ‘why this SP release while hotfix 7 for SP3 was just released at the same time! and NetWorker 8 in restrict availability mode?’. Well, I think personally it is a quick bridging release to taste the new flavors that will be available in NetWorker 8 (of course beside the long list of fixes!). Good, you can start enjoying the new features and enhancements.

Here is a summary over the new features and changes in this release:

Optimized disk reading

NetWorker 7.6 SP4 introduces a new feature to optimize data read performance from the client system during standard file system backups.

While previous releases used fixed 64KB blocks while reading files from a client, NetWorker 7.6 SP4 introduces an intelligent algorithm which chooses an optimal block size value in the range of 64KB and 8MB based on the current read performance of the client system. This discovery occurs during the actual data transfer and does not add any overhead to the backup process, while potentially significantly increasing disk read performance.

Note: Read block size is not related to device block size used for backup, which remains unchanged.

This feature is transparent to the rest of the backup process and does not require any additional configuration.

Dynamic value can be overridden by setting the environment variable NSR_READ_SIZE to a desired block size. For example, NSR_READ_SIZE=65536 forces NetWorker to use 64KB block size during the read process.


By default, the NetWorker client always chooses the Windows VSS system provider for VSS backups. If you want to use a hardware provider or a specific software provider for a particular NetWorker client, enter the following command in the NetWorker client resource Save Operations attribute:


When this command is specified for a NetWorker client, a backup provider is selected based on the following default criteria as specified by Microsoft:

1. If a hardware provider that supports the given volume on the NetWorker client is available, it is selected.

2. If no hardware provider is available, then if any software provider specific to the given NetWorker client volume is available, it is selected.

3. If no hardware provider and no software provider specific to the volumes is available, the Microsoft VSS system provider is selected.

Note: Windows Disaster Recovery backups always use the Windows VSS system provider even if the VSS:VSS_ALLOW_DEFAULT_PROVIDER=yes command is specified for the NetWorker client resource.

DD Boost version 2.4.1 support

The libddboost library in NetWorker 7.6 SP4 has been updated to DD Boost version 2.4.1.

Platforms supporting DD Boost are identified in the EMC NetWorker Software Compatibility Guide.

Data Domain VTLs auto-configurable using jbconfig

The jbconfig command can now be used to auto-configure Data Domain VTLs.

Multiple backup and recovery sessions (save streams) with DD Boost device

Each NetWorker client and storage node installed with DD Boost can now perform up to 60 concurrent backup and recovery sessions (save streams) per DD Boost device. This high use of sessions reduces the number of devices needed and thereby reduces the impact on the Data Domain system performance and maintenance. The resulting performance gain can compare favorably against conventional advanced file type device (AFTD) or virtual tape library (VTL) interfaces that do not allow the same high rate of sessions.

There is no recommended limit on the number of DD Boost devices that can be created. However, the number of devices you use depends on your backup and recovery requirements. Increasing the number of DD Boost devices can impact Data Domain performance and maintenance. Typically, where multiple concurrent recovery sessions (streams) is not a priority, configure device Target and Max Sessions for multiple concurrent save sessions.

Changes to Data Domain licensing

NetWorker 7.6 SP4 Data Domain storage software enablers now support multiple interfaces and network identities. In previous releases, it was recommended to use an ifgroup software configuration of NICs on the Data Domain system to allow multiple storage nodes to use a single network identity and a single Data Domain Storage System Enabler. Although ifgroup is no longer needed to share licensing, bandwidth aggregation is still a valid and recommended use case of ifgroup for DD Boost devices.

The EMC NetWorker Licensing Guide and your EMC sales representative can provide licensing details.

Virtual client connection licenses no longer required

With NetWorker 7.6 SP4, client connection licenses are no longer required for virtual clients.

Jukeboxes can now be configured in AIX LPAR environment

Jukeboxes can now be configured in AIX LPAR environment (AIX versions 6.1 and 7.1).

Support for nwrecover on Solaris 11 platforms

Due to libraries that were previously not supported by Solaris 11 platforms, the nwrecover program could not be used in NetWorker 7.6 SP3 running on Solaris 11.

With NetWorker 7.6 SP4, support for the nwrecover program is available on Solaris 11 platforms and is included in the installation of NetWorker 7.6 SP4 on Solaris 11.

Support for enabling of SELinux on Linux platforms

Previously, mandatory access control architecture SELinux required disabling on Red Hat 5 and 6. With NetWorker 7.6 SP4, you can now enable SELinux for Linux platforms.

Environment variable for disabling CBT for VADP backup

An option is now available in the Application Information tab in NMC to disable CBT.
Setting VADP_DISABLE_CBT=yes disables CBT for VADP backups. CBT is enabled by default.

Option to enable or skip quiescing during VADP backup

An option is now available in the Application Information tab in NMC to enable or skip quiescing during VADP backup.

To control the quiesce options that NetWorker passes to the VC/ESX during VADP backup, specify the VADP_QUIESCE_SNAPSHOT attribute in the Application Information tab NMC as follows:

If VADP_QUIESCE_SNAPSHOT=Yes , then quiesced snapshots for VM clients are initiated

If VADP_QUIESCE_SNAPSHOT=No , then non-quiesced snapshots for VM clients are initiated. In this case, the snapshot will not be application consistent. EMC does not recommend setting this option.

If this attribute is not specified , then NetWorker initiates quiesced snapshots for VM clients by default.

Note: The attribute VADP_QUIESCE_SNAPSHOT can be applied either at the VM level or proxy level. If applied at the VADP proxy level , all the VMs that use this VADP proxy will be affected.

Get to know more about these features and enhancements in the NetWorker 7.6 SP4 Release Notes from the EMC Powerlink.