Technical white paper

Using HP StoreOnce Backup systems for Oracle database backups

Table of contents

Introduction 2

Technology overview 2 HP StoreOnce Backup systems key features and benefits 2

HP StoreOnce Backup systems in small to large data centers 3 Overview—why StoreOnce for Oracle backup 3 VTL vs. NAS—advantages of each for Oracle backup 3

HP StoreOnce Backup systems for Oracle backup 4 Oracle backup infrastructure components 4 Capacity planning 5 Capacity planning usage models 6 Weekly full and daily incremental backups 7 Using different RMAN parameters affects Oracle backup throughput and deduplication ratios 9

Disaster recovery with local StoreOnce Backup system and remote replication 10

Recovery scenarios 11

Recommendations 11

Conclusion 13

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Introduction In today’s business environment, Oracle database customers rely on the most efficient, high performing, and reliable backup systems. Customers need to protect increasing levels of data while keeping costs under control. In particular, businesses today are concerned about the costs of backing up and archiving important data from mission-critical servers. HP StoreOnce Backup systems provide a disk-based data protection platform while addressing data growth by applying HP StoreOnce deduplication software for efficient, longer term data retention.

This document describes the benefits of using HP StoreOnce Backup systems for Oracle database backups. This document also recommends backup and recovery implementations. The following are key results for backing up Oracle databases using a StoreOnce Backup system:

• Valid targets: HP StoreOnce virtual tape library (VTL) and network-attached storage (NAS) targets are both valid devices for backing up Oracle databases. NAS targets are recommended for Oracle Recovery Manager (RMAN) standalone backups.

• Increased deduplication: Setting the RMAN parameter FILESPERSET to 1 achieves the best overall deduplication ratio.

• Decreased server resources: A weekly full and daily incremental backup schedule uses less server and StoreOnce compute and bandwidth resources during backup than a daily full backup schedule. Backup data will require about the same amount of space on the HP StoreOnce Backup system for each schedule type.

• Increased backup speed: Multiplexed RMAN backups improve throughput performance but may cause a decline in deduplication ratios.

HP StoreOnce Backup systems are disk-based backup systems that deliver leading price-performance and deduplicate Oracle database backup data. The StoreOnce Backup system can be used to automate and consolidate the backup of multiple databases onto a single, rack mountable device while improving reliability by reducing errors caused by media handling. For business environments with remote offices, or a disaster recovery site, the StoreOnce Backup system can be used to replicate data to a central data center or remote facility.

HP StoreOnce Backup systems are ideal for mission-critical application backup data for small to large data centers running key business applications, such as Oracle. Proper configuration of Oracle database backups with a data protection application to the StoreOnce Backup system provides the best backup throughput performance and data deduplication ratios. HP StoreOnce Backup systems integrate seamlessly into current IT environments and offer the flexibility of both VTL and NAS targets for Oracle database backups.

Technology overview

HP StoreOnce Backup systems key features and benefits • HP StoreOnce deduplication, store more data on disk

HP StoreOnce deduplication reduces the disk space required to store backup data sets without affecting backup performance. Retaining more backup data on disk for longer, enables greater data accessibility for rapid restore of lost or corrupt files and reduces downtime.

Deduplication ratios are strongly influenced by two factors—data change rate and retention periods of the data on the deduplication appliance. Low data change rates and data retained for longer periods of time yield higher deduplication ratios.

• Deduplication enabled replication

HP StoreOnce deduplication is the technology enabler for HP StoreOnce Deduplication Enabled replication, which allows fully automated replication over low bandwidth links to a disaster recovery (DR) site, giving Remote Office/Branch Office (ROBO), and small data centers a cost effective DR solution for the first time.

• Rapid restore of data for dependable, worry-free data protection

HP StoreOnce Backup systems offer immediate access to backups for rapid restores. StoreOnce deduplication allows more data to be stored closer to the data center for longer periods of time, which offers immediate access for rapid restores.

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• Automate, simplify, and improve the backup process

HP StoreOnce Backup systems automate your backup processes allowing you to reduce the time spent managing your data protection. Implementing hands-free, unattended daily backup is especially valuable for environments with limited IT resources, such as remote or branch offices.

StoreOnce systems can backup multiple servers via a standard Ethernet or Fibre Channel (FC) network simultaneously to a disk-based solution at peak speeds of up to 100 TB per hour instead of sequentially to a tape drive or autoloader—meaning that you can substantially reduce your backup window.

StoreOnce systems can be intuitively managed and configured by using the built-in Web browsers administrative interface. And, for larger deployments of replicating StoreOnce appliances, the StoreOnce Replication Manager can monitor multiple backup systems throughout the data center. StoreOnce systems are self-managing backup appliances that require little, if any, routine maintenance. Unlike other disk-based storage devices, StoreOnce systems do not require virus protection or logical unit number (LUN) provisioning.

HP StoreOnce Backup systems in small to large data centers

Overview—why StoreOnce for Oracle backup As data center customers prepare to upgrade or migrate their data protection environments, an opportunity exists to improve functionality, performance, and total cost of ownership (TCO) with HP StoreOnce Backup systems. Customers with business critical Oracle databases may wish to migrate or consolidate disparate backup targets to a scalable StoreOnce system.

Migration of Oracle backup from traditional physical tape devices to the StoreOnce Backup system can be seamless because customers may use existing processes and policies, and Oracle RMAN scripts on the new platform. Also, customers with complex backup schedules and major databases like Oracle will find the StoreOnce Backup system to be a platform that provides an opportunity to migrate to a disk-to-disk backup environment maintaining existing processes used with physical tape using VTL.

Customers who use NAS file devices on general purpose shares that backup targets may migrate to a StoreOnce Backup system to mitigate contention and performance issues found in I/O intensive backups, business, and other applications sharing the same storage array.

VTL vs. NAS—advantages of each for Oracle backup HP StoreOnce Backup systems may be configured with VTL and NAS targets for backup of Oracle databases. This section describes VTL and NAS configuration differences and HP recommended uses. StoreOnce Backup systems are designed as target storage for backup applications that need rapid restores and reduced backup windows. As such, a StoreOnce Backup system configured as VTL or NAS uniquely offers:

• Backup to disk, including embedded applications like RMAN, the Oracle built-in backup and recovery utility

• Easier setup and maintenance

• Data deduplication, allowing more backup data to be retained on disk for longer periods

• Data replication for cost-effective offsite storage

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VTL and NAS configurations benefit from the same deduplication and replication features; however note the comparisons and recommendations in table 1.

Table 1. Comparison of NAS targets and Virtual Tape devices

VTL targets NAS targets

Recommended for customers looking to leverage their current investment in tape-based processes and software; easing migration using the same backup policies and Oracle RMAN scripts.

Recommended for customers with non-tape environments who are used to the simpler method of backup and recovery. HP does NOT recommend using StoreOnce NAS targets as general purpose NAS shares.

Appears to the backup application as physically connected tape devices, with backup and recovery jobs managed in the same manner as with a physical tape device.

Seen by the operating system, application, and users as an NFS or CIFS disk share.

Acts as a staging post to tape because backups are in tape format; supports tape offload using a backup application copy feature.

Enables use of backup application functionality that is only available with file shares, such as Disk-to-Disk-to-Tape implementations.

Requires a backup application that supports backup to tape and media management.

May be used with backup applications that do not support backup to tape. NAS shares are ideal for RMAN standalone backups.

Integrates into the current backup routine and requires no special backup jobs.

Requires a new backup job, but is simple to set up.

May require purchase of a “tape backup” license for the backup application.

Licensing is unique for each backup application.

HP StoreOnce Backup systems for Oracle backup An important part of Oracle database administration is maintaining a consistent set of data. When data is lost due to user error, system failure, or site catastrophe there is a need for data recovery. The HP StoreOnce Backup system, integrated with a well-planned data protection strategy, includes regular Oracle database backups to maintain a consistent set of data for recovery purposes.

Oracle backup infrastructure components To successfully recover an Oracle database from all types of failure the following files may be required:

• The last backup of the control file

• The last backup of all datafiles

• All archived redo logs since the last backup was taken (if the database is in archive log mode)

• Copies of configuration files such as the server parameter file, tnsnames.ora, and listener.ora

It is common practice to do daily backups of the control file, datafiles, parameter file, tnsnames.ora, and listener.ora. Archived redo logs are backed up throughout each day as necessary.

HP StoreOnce Backup systems do not deduplicate across VTL or NAS shares. Each VTL and NAS share is an independent deduplication domain. Table 2 outlines the StoreOnce system VTL or NAS shares recommended for Oracle database backup.

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Table 2. StoreOnce Backup system VTL or NAS shares recommended for Oracle database backup

Oracle backup Recommended StoreOnce Backup device configuration

Control file and datafiles Create a unique StoreOnce Backup system VTL or NAS share specifically for the control file and datafiles to realize the best deduplication ratios

Archived redo logs Create a unique StoreOnce Backup system VTL or NAS share specifically for archived redo logs—the logs represent new or changed data in the database which will not deduplicate as well as datafiles

Parameter file, tnsnames.ora, listener.ora Include in a standard file system backup and send to a StoreOnce Backup system VTL or NAS share created specifically for the file system backups

Capacity planning The amount of required backup storage for Oracle database backups depends on the following:

• Size of the Oracle database

• Size of the archived redo logs (if running in archive log mode)

• Site backup retention policy

• Type (full, incremental, or differential) and frequency of backups

• Rate of change of the Oracle database

• The deduplication ratio achieved by the StoreOnce Backup system

Note:

The rate of change of a data refers to the amount of data that would be contained in an incremental backup as a percentage of a full backup. A 100 GB full backup with a subsequent 5 GB incremental backup before the next full backup would be a 5 percent rate of change.

An Oracle administrator may desire to store up to a month’s backups on the StoreOnce Backup system for quick recovery access. Data deduplication provides more backup space without increasing the physical capacity of the backup device; however, a dynamic Oracle database with changing data affects the backup data deduplication ratio.

Figure 1 shows the data rate of change effect on deduplication ratios when backing up an Oracle database to a StoreOnce Backup system. In performing these tests, HP used TPC-C benchmark standard data. For the following chart, rows and columns in the database were updated between each backup until the desired rate of change was reached.

Figure 1. Oracle database rate of change effect on HP StoreOnce Backup system deduplication ratios

4% 8% 12% 16% 20%

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Database rate of change between each backup

StoreOnce deduplication ratio relative to the database rate of change

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Capacity planning usage models An Oracle environment with a 14-day backup data retention requirement can have several StoreOnce backup usage models. Usage models change, based on parameters such as the following:

• Backup schedule type

– Daily full backups deduplicate well but use more server and StoreOnce compute and bandwidth resources during a backup.

– Weekly full with daily incremental backups do not deduplicate as well but use less compute and bandwidth resources. The end-to-end data compaction for weekly full with daily incremental backup schedules is comparable to daily full backups and may be slightly better.

Note:

Data compaction refers to the removal of redundant information from a backup set prior to storing on a backup device. Incremental backups, deduplication, and compression are all methods for removing redundant data from a backup set.

• Database daily rate of change—Lower change rates result in better deduplication ratios and require less StoreOnce backup storage.

• Backup block size—The backup block size set by the data protection application may affect StoreOnce deduplication ratios.

• RMAN parameters

– FILESPERSET—Using a lower FILESPERSET value results in better deduplication ratios. Refer to the section Using different RMAN parameters affects Oracle throughput and deduplication ratios below for additional information on FILESPERSET.

– ALLOCATE CHANNELS—Allocating multiple channels in RMAN, in combination with other parameters, may affect StoreOnce deduplication ratios.

Figure 2 compares six usage models for Oracle backups with the following common characteristics:

• DB size: 1 TB

• Backup schedule: Daily

• Retention period: 14 days

Each usage model shows the overall size of the Oracle DB backup data without deduplication (14 daily backups of 1 TB each) versus the size of the data on the StoreOnce Backup system after deduplication.

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Figure 2. Data compaction comparison of different backup types

Note: The deduplication ratios are a factor of the data type, daily rate of change, FILESPERSET, ALLOCATE CHANNELS, backup schedule type and backup retention period as observed and measured during testing. Deduplication ratios will vary according to the environment.

Weekly full and daily incremental backups Many backup environments use a weekly full and daily incremental backup schedule. Some characteristics of full and incremental backups are:

• Full backups include both the changed and unchanged data in a data set.

• Incremental backups only include changed data in a data set.

• Changed data does not deduplicate as well as unchanged data, so incremental backups may not deduplicate as well as full backups.

• Incremental backups are usually much quicker than full backups and use fewer resources, which results in less impact to the backup server, disk storage device, and StoreOnce Backup system.

• End-to-end data compaction is greater for schedules that include incremental backups when compared with daily full backup schedules. The result is less storage space usage on the StoreOnce Backup system even though deduplication ratios are lower for incremental backups.

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Figure 3 illustrates how StoreOnce Backup system deduplication ratios trend over time for varying database rates of change. Deduplication ratios rise quickly and are maintained over time.

Figure 3. Oracle backup deduplication ratio trend over time

Figure 4 illustrates how the StoreOnce Backup system maintains multiplexed backup throughput speed over time as the StoreOnce Backup system storage device starts to fill.

Figure 4. Oracle multiplexed backup throughput over time

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Number of full backups

Oracle full backup deduplication ratio—Varying rate of change FILESPERSET=1

4% Rate of Change

8% Rate of Change

12% Rate of Change

16% Rate of Change

20% Rate of Change

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Number of full backups

Oracle multiplexed full backup throughput as StoreOnce Backup system fills

StoreOnce 12% Full

StoreOnce 40% Full

StoreOnce 66% Full

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Using different RMAN parameters affects Oracle backup throughput and deduplication ratios Oracle RMAN statements and parameters can be used to control backup data streams. HP recommends reading Oracle documentation for a full explanation of all RMAN statements and parameters. This document will focus on the effects the “ALLOCATE CHANNEL” statement and FILESPERSET parameter have on backup data streams.

RMAN backups store data in a backup structure called a backup set, which is the smallest unit of an RMAN backup. A backup set contains data from one or more datafiles, tablespaces, archive logs, control file, or parameter file (SPFILE).

The number of backup sets in a backup and how many input files there are in a backup set depend on RMAN statements and parameters such as:

• ALLOCATE CHANNEL—This statement allocates a channel to a media manager, such as a backup application, or to a local backup device such as a StoreOnce NAS device. Multiple ALLOCATE CHANNEL statements may be used to open multiple channels simultaneously.

• FILESPERSET—This parameter specifies the number of files in a backup set. FILESPERSET is set dynamically unless specified in the BACKUP statement.

• MAXOPENFILES—This parameter specifies how many files may be open in an allocated channel. The MAXOPENFILES default is eight unless specified in the ALLOCATE CHANNEL statement.

HP recommends the following when using RMAN to backup to a StoreOnce Backup system:

• FILESPERSET should always be set to 1. This ensures that RMAN will not interleave data in a backup set, which results in much better data deduplication.

• Use ALLOCATE CHANNEL to open multiple channels simultaneously to the media manager or local backup device. This allows RMAN to multiplex backup data streams, resulting in much better backup throughput and has a minimal effect on data deduplication ratios. The optimal number of allocated channels would depend on the environment.

Figure 5. Illustrates how allocating multiple channels increases backup throughput performance.

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Oracle backup throughput—1% Rate of change

Number of full backups

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RMAN Direct Full Backup FILESPERSET=1 ALLOCATED CHANNELS=8

RMAN w/Backup App Full Backup FILESPERSET=1 ALLOCATED CHANNELS=8

RMAN w/Backup App Full Backup FILESPERSET=3 ALLOCATED CHANNELS=4

RMAN w/Backup App Full+Incr. Backup FILESPERSET=1 ALLOCATED CHANNELS=1

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Figure 6 illustrates how StoreOnce backup deduplication ratios are affected based on the RMAN parameter FILESPERSET and the number of allocated channels.

Figure 6. Oracle backup deduplication ratio trend over time

Disaster recovery with local StoreOnce Backup system and remote replication Most companies recognize the importance of a robust data protection strategy. Enterprise-level customers are likely to invest in site disaster recovery. In addition, many companies, large and small, are protecting Oracle database applications in remote offices where untrained IT staff are expected to manage a daily backup process—generally involving the changing of physical tapes, which is a process prone to human error.

HP Low bandwidth replication (LBR), available on its StoreOnce Backup systems, offers the solution to both of these problems by allowing local Oracle backup data to be replicated between sites in a reliable, automated manner. This provides the following flexibility in Oracle data recovery:

• Oracle databases can be recovered at the StoreOnce source site (original Oracle database location).

• Oracle databases can be recovered at the StoreOnce target site (remote location).

• If a total disaster of the Oracle database source site occurs, the target site StoreOnce can be shipped to the source site or the backup data can be replicated back to the source site for complete Oracle database recovery.

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Oracle deduplication ratio—1% Rate of change

Number of full backups

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RMAN Direct Full Backup FILESPERSET=1 ALLOCATED CHANNELS=8

RMAN w/Backup App Full Backup FILESPERSET=1 ALLOCATED CHANNELS=8

RMAN w/Backup App Full Backup FILESPERSET=3 ALLOCATED CHANNELS=4

RMAN w/Backup App Full+Incr. Backup FILESPERSET=1 ALLOCATED CHANNELS=1

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Recovery scenarios Figure 7 illustrates disaster recovery scenarios that might occur and the recovery path available when pairing two StoreOnce Backup systems for remote replication.

Figure 7. Recovery scenarios

Recommendations

• Oracle daily full backups vs. weekly full with daily incremental backups

– Daily full backups deduplicate at a much higher rate than weekly full with daily incremental backups but require more server and StoreOnce Backup system processing resources.

– The StoreOnce Backup system data storage required is roughly the same for each type of backup schedule over an extended time period.

– Daily full backups deduplicate better but weekly full with daily incremental backups send much less data to the StoreOnce system for deduplication processing.

– If daily full backups are not required, HP recommends a backup schedule that includes incremental backups to reduce the resource load required for Oracle database backup.

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• Oracle backups with ARCHIVELOG mode vs. NOARCHIVELOG mode

– The backup of an Oracle database running in ARCHIVELOG mode may take place with the database open. Full database datafile backups have a relatively high deduplication ratio when compared to archive log backups, as archived redo logs tend to be more “unique” data types by nature.

– StoreOnce Backup system storage capacity required for archive log backups is roughly half of the actual size of the data.

– When an Oracle database is running in NOARCHIVELOG mode, the only valid database backup is made with the database mounted after a consistent shutdown. There are no archive logs to backup, so the overall data deduplication ratio will be much higher.

• RMAN is unable to manage tape media when used to backup a database without a backup application. HP recommends using StoreOnce Backup system NAS shares for RMAN standalone backups where media management is not required.

• Multiplexing Oracle database backups to the StoreOnce Backup system

– The StoreOnce Backup system is able to obtain higher overall throughput ratios when there are multiple VTL tape devices or NAS shares used simultaneously, or when writing multiple datafiles concurrently to the same device or share; however there may be a decline in the deduplication ratio of Oracle datafile backups.

– RMAN can simultaneously read multiple datafiles from disk by setting the value of the MAXOPENFILES parameter. The FILESPERSET parameter determines how many datafiles to put in each backup set. To open multiple channels to the media manager or backup device simultaneously, use multiple ALLOCATE CHANNEL statements.

– Interleaving multiplexed backups to the same StoreOnce Backup system VTL tape device or NAS share is likely to cause a decline in the deduplication ratio.

– HP testing of multiplexed Oracle RMAN backups showed that to obtain the best deduplication ratio with good backup throughput, set the FILESPERSET parameter to 1 and allocate multiple backup channels.

• Disaster recovery

– StoreOnce remote replication offers a low bandwidth replication solution to and from remote sites, which is ideal for server disaster recovery.

– Oracle backups through a comprehensive data protection solution to a StoreOnce pair configured with remote replication provides recovery for local disk failures, complete server failure, or complete site failures by keeping server backup copies at local and remote sites.

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Conclusion Oracle customers demand an efficient, reliable data growth management backup system environment while keeping costs under control. HP provides a variety of reliable data protection storage solutions that address such requirements. HP StoreOnce Backup systems is one such solution. StoreOnce Backup systems offer high performance and reliability while addressing data growth through HP StoreOnce data deduplication technology for small to large customers. StoreOnce Backup systems integrate easily with leading data protection products to protect important data for mission-critical applications. Combining HP StoreOnce Backup systems with leading data protection products provides a comprehensive data protection solution for Oracle application data.

Call to action Address your requirements for an efficient, reliable, data-growth management backup system in an Oracle environment, while keeping costs under control, by combining HP StoreOnce Backup systems with leading data protection products. To learn how, visit: hp.com/go/storeonce.

HP StoreOnce Backup System user guide http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c02295179/c02295179.pdf

HP StoreOnce Backup systems Linux and UNIX® configuration guide http://h20000.www2.hp.com/bc/docs/support/SupportManual/c02299831/c02299831.pdf

HP StoreOnce Backup systems Best Practices Guide http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02511912/c02511912.pdf

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