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Netting Out NetBackup

NetBackup 7.1 Features - Other minor enhancements - Part 1 of 2

Created: 17 Mar 2011 • Updated: 22 Jan 2013 • 1 comment
Dave High's picture
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Welcome to NetBackup 7.1! This series of blogs will provide additional information into the key features of NetBackup 7.1 continuing with a look at some of the minor features including:

  • SharePoint Agent Enhancements
  • Exchange Agent Enhancements
  • Oracle Deduplication improvements
  • Duplication performance enhancements

SharePoint Agent Enhancements

Previous releases of NetBackup included powerful features for protecting Microsoft SharePoint databases. NetBackup 7.1 adds two minor but important additional features - support for SharePoint 2010 secondary filegroups and the ability to redirect granular recovery of web applications to a different farm. The additional SharePoint agent features are focused on improving compatibility with new features in SharePoint 2010 and providing a frequently requested capability.

Support for SharePoint 2010 secondary filegroups enables customers who use the secondary file groups feature to protect their SharePoint 2010 environments using NetBackup. The ability to redirect granular recovery of web applications to a different farm provides a useful aid to customers interested in ‘cloning’ data for test and development purposes and transferring data between SharePoint farms.

Secondary Filegroup Support

The vast majority of the data in a Microsoft SharePoint environment is stored as Microsoft SQL Server databases. Microsoft SQL Server is a mature and complex product with many performance-enhancing features, not all of which are supported by SharePoint. A prime example of this is the concept of multiple filegroups. SQL Server allows a single database to be broken up into multiple files. Several of these files can be associated with each other to constitute a “filegroup”. This is illustrated in the Figure below.

SharePoint 2010 adds support for secondary files and filegroups, and Microsoft now recommends using multiple files in SharePoint 2010 databases for performance reasons. Prior to NetBackup 7.1 the NetBackup Agent for Microsoft SharePoint did not support secondary files and filegroups and  it was not possible to back up a SharePoint 2010 content database that used them. In NetBackup 7.1 the NetBackup Agent for Microsoft SharePoint provides full support for secondary files and filegroups transparently and requires no additional configuration to work with SharePoint 2010 content database that used them.

Web Application Redirection

Taken together, all the components of a SharePoint environment are called a “farm”. Generally all granular-enabled backups and restores take place within a single farm. On occasion, however, it is useful to be able to recover a SharePoint component to a farm different from the one in which it originated. This is most frequently used in organizations that maintain separate test and production farms.

Earlier versions of the NetBackup SharePoint agent did not permit direct recovery of objects to a different farm, but in some cases it was possible to work around this limitation. For example, the SharePoint agent allowed a redirect of a file object (such as a Word or Excel document in a SharePoint document library) to a file share on a disk rather than directly to a SharePoint farm. Once the object is in a disk directory it can be uploaded to a different farm by the SharePoint administrator. However, there was no way to redirect most other objects.

NetBackup 7.1 introduces the ability to redirect a web application to a different farm. This will satisfy a substantial number of customers who have been asking for a redirection feature.

Exchange Agent Enhancements

NetBackup 7.1 adds two minor but important additional features to the Exchange Agent backups - wildcard support in the backup selection list and accelerated browsing for granular restore technology (GRT) backups.

Wildcard backup selection

Exchange backup policies usually use a single high-level entry in a policy’s backup selection list to specify which databases to back up (e.g., “Microsoft Information Store:\” or “Microsoft Exchange Database Availability Groups:\”). This ensures that all databases on an Exchange server are backed up. However in some situations the Exchange administrator wants to control precisely which databases are backed up, and in what order.

Prior to NetBackup 7.1 it was necessary to spell out the name of each database in a backup selection list. This made maintenance of the policy more difficult, as it was necessary to edit the list each time a database was added, removed, or renamed.  The ability to use wildcards in the backup selection list will simplify the creation and maintenance of selective Exchange backup policies.

Accelerated GRT image browsing

NetBackup’s support for granular recovery of individual mailbox items is one of the most powerful features of the Exchange agent, but it’s not without issues. Prior to NetBackup 7.1 the browsing process can be very slow as NetBackup does a “live browse” of the database structure, using the Exchange server to assist in locating and enumerating each item.

In NetBackup 7.1 the Exchange database is partially enumerated during the GRT backup and the resulting information (down as far as the top of each individual’s mailbox) is stored in the NetBackup catalog. As a result, when an administrator examines an Exchange GRT backup in order to perform a restore, multiple database levels open up almost instantly, with no long pauses.

Oracle Deduplication Improvements

The NetBackup product offers a number of integrated “deduplication” solutions.  The NetBackup Oracle Agent has been enhanced to fully utilize the benefits these Deduplication solutions provide. Now, deduplicating Oracle data can be performed as close to the data source as desired.  Available options are:

  • Deduplicate on NetBackup clients
  • Deduplicate on NetBackup media servers
  • Deduplicate on destination disk (OST compatible devices)
  • Deduplicate using NetBackup PureDisk, including at remote offices

Enterprise IT faces many challenges when it comes to protecting Oracle databases. As databases grow in size, backup solutions that once worked well for smaller databases may no longer address the needs of larger Oracle databases.  Some of the challenges created by growing Oracle environments can be overcome by utilizing Deduplication technology. Deduplication improves the backup process by reducing storage consumption for backup and archiving, and by reducing bandwidth requirements for data movement.

Oracle database backups are predominately streamed, meaning RMAN will read the Oracle data files and send streams of data to NetBackup buffers.  While streaming, RMAN tries to optimize the process by multiplexing, compressing and interlacing data.  This process is counterproductive for ensuring optimal Deduplication, because there is no guarantee that the streamed data will be presented in the same order making it difficult to create segments identical to those created in previous backups.  Deduplication relies on the ability to create segments and compare their content to the segments stored previously.

The NetBackup Oracle Agent provides alternative backup methods which preserve the physical layout of the Oracle blocks, enabling much higher Deduplication rates. So what are the options and benefits of each? Read on.

Client Side Optimized Deduplication

If the Oracle server is not heavily utilized, perform deduplication on the server itself. An oracle server is considered a NetBackup Client, and by performing deduplication on the client only changed blocks will be sent across the network. This is comparable to the amount of data generated during an incremental backup.

The benefit of this option is that, from Oracle’s point of view, a full backup can be performed every day while sending only the changed segments. In order words, the equivalent of an incremental backup is created, but at the time of recovery, the restore is from the last full backup (there is no need to apply additional increments).

Deduplicated Off-host Backup

If the performance of the Oracle server is a bottleneck, or the backup window is becoming too short, or the network is over-utilized, the information can deduplicated off-host. Combining the Oracle Agent with Snapshot Client you can perform an off-host backup and/or retain a snapshot as a recovery option, referred to as Instant Recovery. Some form of Snapshot technology is required for this configuration. NetBackup supports software and hardware based snapshot providers. Additional steps are not needed to accomplish excellent deduplication rates. Oracle Agent’s deduplication feature is invoked by default.

Media Server Deduplication

Media Server Deduplication is another way to off-load the backup’s performance overhead from the Oracle server. It is suitable for environments where network is not a bottleneck and the backup window is sufficient. It is also recommended for protecting Oracle RAC, where one or more nodes are also dedicated media server(s).

As you have seen, NetBackup 7.1 offers a number of different ways to protect Oracle data, and move the load crated by deduplication hashing to where it makes the most sense.

Duplication Performance Improvements

Many customers have expressed disappointment at the performance observed when duplicating (not to be confused with deduplicating) backups from disk to tape. This has been a particular problem for customers using Storage Lifecycle Policies to ‘stage’ frequent small backups such as application transaction logs prior to writing them to tape with many customers seeing duplication rates to fast tape drives as low as 30 MB/sec. NetBackup 7.1 introduces two enhancements that combine to reduce processing overhead involved in duplicating backups from disk to tape and, in doing so, dramatically reduces the time required to duplicate smaller backups. 

The first of these two enhancements is read-side chaining for disk based backup.  This is similar to the write-side chaining feature introduced in NetBackup 6.0 and causes the resource broker to retain its lock on the source disk until all outstanding duplications are completed rather than releasing and reallocating the disk between each image duplication.

The second enhancement is deferred file mark writing for tape.  Although tape speeds have increased significantly in recent years the time required to write file marks has remained largely unchanged.  This means that writing a file mark now takes significantly longer relative to the time required to write a backup image than it did a few years back.  In NetBackup 7.1 instead of waiting for a file mark to be written for each image duplicated from disk (or non-multiplexed tape) to tape NetBackup now waits for a file mark to be written after a number of images (8 by default) or when an image is above a certain size (1 GB by default).  It is very important to understand that this doesn’t change the tape format at all.  It is also important to understand that this enhancement will likely benefit only those that write to physical tape. Performance when using VTL’s will not be changed with this second enhancement.

The combination of these two enhancements significantly reduces the ‘dwell’ time during duplications resulting in faster end-to-end duplication speeds, particularly for large numbers of small images being staged to tape.

A separate set of enhancements also serve to increase the performance when writing and duplicating multiplexed backups.  There is a general perception among users of SLPs and DSSUs that duplication should be faster than it usually is, particularly when duplicating from disk to tape.

Customers who are using either the vault option, DSSUs or SLPs to duplicate backups from disk to tape are likely to see the duplication process run faster in most cases.  The degree of performance gain will vary from customer to customer but, as a general rule, the smaller the backups being staged the greater the potential performance gain in duplicating to tape. Customers who are using multiplexing and duplicating from tape to tape (both physical and virtual tape) can also expect to see performance improvements and reduced duplication times.

Hopefully this information on the minor features of NetBackup 7.1. Join us tomorrow for the final blog entry providing an overview of the rest of the minor features in NetBackup 7.1.

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WHITE EAGLE's picture

A separate set of enhancements also serve to increase the performance when writing and duplicating multiplexed bacyps,general perception among users of SLP and DSSUS, why the degree of performance of gain will vary from different customers?

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