vRanger 7.8.1 - Integration Guide for EMC Data Domain Boost (DD Boost)

Advanced Load Balancing and Link Failover

Advanced Load Balancing and Link Failover

vRanger supports a single host name and IP address per repository. For EMC® Data Domain® systems that require multiple 1 GbE links to obtain full system performance, you must set up multiple storage servers on the Data Domain systems — one per interface — and target the backup policies to different storage servers to spread the load on the interfaces.

The Advanced Load Balancing and Link Failover feature allows for combining multiple Ethernet links into a group. Only one of the interfaces on the Data Domain system is registered with vRanger. The EMC® Data Domain® Boost (DD Boost™) Library negotiates with the Data Domain system on the interface registered with vRanger to obtain an interface to send the data. The load balancing provides higher physical throughput to the Data Domain system compared to configuring the interfaces into a virtual interface using Ethernet level aggregation.

The Data Domain system load balances the connections coming in from multiple vRanger instances on all the interfaces in the group. The load balancing is transparent to vRanger. Because Advanced Load Balancing and Link Failover works at the DD Boost Library software layer, it is seamless to the underlying network connectivity and supports both physical and virtual interfaces.

The data transfer is load balanced based on the number of connections outstanding on the interfaces. Only connections for backup and restore jobs are load balanced.

 

NOTE: The replication connection between the Data Domain systems is not part of the load balancing. A single IP address is used for the target Data Domain system.

 

IMPORTANT: Quest recommends that you exclude one interface from the ifgroup and reserve it for the replication path between the source and target Data Domain systems.

The Advanced Load Balancing and Link Failover feature can be used with other network layer aggregation and failover technologies. The Advanced Load Balancing and Link Failover functionality also works with other network layer functionality on the Data Domain systems, including VLAN tagging and IP aliasing. This functionality allows additional flexibility in segregating traffic into multiple virtual networks, which run over the same physical links on the Data Domain system.

The benefits of Advanced Load Balancing and Link Failover are as follows:

•	Eliminates the need to register multiple storage servers — one for each interface — with vRanger, which can potentially simplify installation management.

•	If one of the interfaces in the group goes down while the Data Domain system is still operational, the subsequent incoming backup jobs are routed to the available interfaces.

•	The backup and restore jobs are automatically load balanced on multiple interfaces in the group, which can potentially result in higher utilization of the links.

•	All in-flight jobs to the failed interface transparently are failed over to healthy operational links. From the point of view of vRanger, the jobs continue uninterrupted.

Configuration restrictions

•	The interfaces can be added only to the group using an IP address.

•	Even though the Advanced Load Balancing and Link Failover feature works with mixed 1GbE interfaces and 10 GbE interfaces in a group, it is not a recommended setup. Quest recommends that you have interfaces with the same link speed in a group.

•	Since only one interface group is supported on the EMC® Data Domain® system, for connecting more than one backup server, a switch is needed in the middle.

Managed file replication

Managed file replication

File replication replicates a single file. The replication request is initiated by the application. By default, the backup servers set up replication jobs between two EMC® Data Domain® systems after authenticating them using the pre-configured EMC® Data Domain® Boost (DD Boost™) user name and password. If the replication feature is enabled, when an optimized job is set up by backup servers, the session between the source and destination Data Domain systems is encrypted using Secure Sockets Layer (SSL), ensuring all image data and metadata is sent encrypted over the WAN.

Enabling this option on Data Domain system is transparent to the data protection application. When the data protection application requests Data Domain system to perform a replication job, the source and destination systems negotiate automatically to perform encryption without knowledge of the requesting data protection application. Replication uses the ADH-AES256-SHA cipher suite. There is no ability to configure a different suite.

Replication is available to a Data Domain system with an installed Replicator license, and applies to all replication jobs on that system. Both the source and the destination Data Domain systems that are participating in replication jobs must have this option enabled for it to take effect.

Replication can be used with the encryption of data-at-rest feature available on Data Domain operating system with the optional Encryption license. When replication is used with the encryption of data-at-rest feature, the encrypted backup image data is encrypted again using SSL for sending over WAN.

Replication notes

Replication notes

•	Both the source and the destination EMC® Data Domain® systems must be running Data Domain OS 5.2 or later to use this feature.

•	Enabling this feature does not require restarting the file system on a Data Domain system.

•	The low-bandwidth optimization and the encryption options can be used with each other.

Low-bandwidth optimization

Low-bandwidth optimization

The low-bandwidth Replicator option reduces the WAN bandwidth utilization. This option is useful if replication is being performed over a low-bandwidth network (WAN) link. This option provides additional compression during data transfer and is recommended only replication jobs that occur over WAN links that have fewer than 6 Mb/s of available bandwidth.

The low-bandwidth optimization option is available to EMC® Data Domain®s systems with an installed Replicator license. The option is enabled on a Data Domain system and applies to all replication jobs on that system.

Enabling this option on Data Domain system is transparent to the data protection application. When the data protection application requests a Data Domain system to perform a replication job, the source and destination systems automatically perform the additional compression without involving the requesting data protection application.

Each Data Domain system wanting to participate in low-bandwidth replication must have this option enabled.