An Oracle White Paper March Backup and Recovery Strategies for the Oracle Database Appliance

Transcription

1 An Oracle White Paper March 2012 Backup and Recovery Strategies for the Oracle Database Appliance 1

2 Oracle Database Appliance The Oracle Database Appliance is an engineered-system; a pre-configured bundle of hardware and software, that saves time and money by simplifying the deployment, maintenance, and support, of a high availability database solution - all supported by a single vendor, Oracle. The Database Appliance is a fully integrated system of software, servers, storage and networking in a single box capable of supporting a wide range of home grown and packaged OLTP and Data Warehousing applications. It s built using the latest generation of the world s most popular database, Oracle Database 11g, and incorporates time-tested Oracle technologies, including Oracle Real Application Clusters, Oracle Clusterware and Oracle Automatic Storage Management Oracle Database Appliance Backup and Recovery Remains the Same The Database Appliance is a robust system, protecting your data on a number of levels, but protection is not complete without external copies that capture the state of the database at a given point in time to protect against risks like corruption, accidental deletions, or system failure. Additionally you may have requirements to archive data for long period of time. Each implementation will have its own requirements for service levels in terms of retention, recovery time and recovery point. Backup for the Oracle Database Appliance can be designed to meet any and all of these requirements. For the sake of this discussion, backup is defined as the process of making copies of data which may be used after a data loss event to restore a system to the state that existed at the time the copy was made. Most enterprises have service level agreements in place that specify how long recovery can take, called a Recovery Time Objective (RTO) and how long of a time lapse is allowed between a potential failure and the time the last backup copy was made, called Recovery Point Objective (RPO.) In the case of a database, good backup practices should provide a recovery point very close to the time of failure through the use of redo logs. An additional consideration is the length of time that data must be retained for, either for contractual or regulatory requirements. It is the intent of this white paper to describe ways to meet data protection objectives in efficient, cost effective ways. Backup may be to disk, to tape, or both disk and tape to meet these requirements. Best practices for protecting the Database Appliance against these risks dictates that the database be in archivelog mode and that Recovery Manager, better known as RMAN, is used to backup the database. Otherwise a whole-database backup cannot be accomplished without shutting the database down. Backing up the Oracle Database Appliance is no different than doing a database backup or restore and recovery on any other platform. Some users of the Oracle Database Appliance 2

3 may be first time users of Oracle or may not be familiar with the options they have for performing backups. This paper presents three ways this task can be accomplished: Backup to a Fast Recovery Area (FRA) on the direct-attached disk Backup to an external File System - such as that available with Network Attached Storage Backup or archive to tape Additionally, there are two ways to automate the backup process Enterprise Manager Database Control or Grid Control Scripting Backup Destinations A Word About Oracle Database Appliance Storage Devices Oracle Database Appliance storage hardware includes integrated storage for both operational files (the operating system, Oracle Grid Infrastructure home, Oracle Database homes, the Oracle Appliance Manager utilities, and other tools), user data (database files), and redo log files. Operational files for each server are stored on mirrored internal system disks. User data is stored on twenty Serial Attached SCSI (SAS) disks in the shared storage bay, these disks can be accessed by either server. Database redo-log files are stored on four Solid State Disks (SSD) in the shared storage bay. Oracle Automatic Storage Management (Oracle ASM) provides three-way mirroring for your data and log files. The SAS disks provides storage for two disk groups, one for database related files (called +DATA) and one for the Fast Recovery Area (called +RECO), which includes multiplexed copies of online redo logs and control files. Log files are stored on a three-way mirrored disk group on SSD called +REDO. Backup to Flash Recovery Area The Flash Recovery Area (FRA), called +RECO on the Oracle Database Appliance, is a disk location that you can use to store recovery-related files such as control file and online redo log copies, archived redo logs, flashback logs, and RMAN backups. Typically, the FRA disk group will be twice the size of the DATA disk group, since it must hold all backups. The database and RMAN manage the files in the flash recovery area automatically. Flashback logs will frequently provide the fastest route to restoring a system when a problem has occurred. RMAN backups to the FRA provide protection for problems with a larger scope, but are vulnerable to any disaster that might befall that system. True data protection would call for backup copies stored off of the Appliance, perhaps even off-site. In the case of Oracle Database Appliance, extending the FRA to an external device for the purpose of backups has the added advantage of reducing the space requirement for +RECO on the device and preserving the finite disk space for data. 3

4 Backup to a File System Network Attached Storage (NAS) We have seen that moving backup off of the Appliance to an external device has two advantages, it mitigates the risk of storing backup data on the device itself, and it preserves disk space for data on the appliance. This section will talk about using disk space for an RMAN backup on an external, but local, device. This solution requires that the DBA devise a file naming scheme, procure suitable disk space on a system somewhere on the network and then manage the files over time. The ZFS Storage Appliance represents the most cost effective way to provide external backups, and it provides a number of other advantages as well. The ZFS Storage Appliance is easily mounted from the Database Appliance via NFS, the ZFS Storage Appliance can be simply used to provide ample space for multiple Level 0 (full) backups, as best practices recommends, as well as incremental backups. These backups, while not quite as fast as flashback restores, are readily available and provide a very fast restore. If a whole-database backup is done cold - with the database shutdown - the backup is considered consistent and can be opened without recovery and without using the resetlogs command. This provides a very fast restore time. If the backup is performed while the database is open, the backup will be considered inconsistent and requires the use of archived redo logs to make the data current. This hot backup approach allows use of the database to continue uninterrupted by backups and is often used to provide backups with a shorter Recovery Point, as backups can be taken more frequently, even during the business day. The Oracle Database Appliance is equipped with both 1 Gigabit Ethernet connectivity and 10 Gigabit Connectivity, the ZFS Storage Appliance offers 1 Gigabit Ethernet connectivity as a standard feature and 10 Gigabit Ethernet as an option. As the 10GbE connection is typically used for user connectivity, it is recommended that the 1 GbE connections, or a Virtual LAN on the 10GbE interface, is used for writing RMAN backups to the Storage Appliance. As alluded to earlier, using the ZFS Storage Appliance provides other advantages. One of those advantages is when you need to maintain an offsite copy of your data. An easy and 4

5 inexpensive way to protect against catastrophic failure at a site is to use the ZFS Storage Appliance s asynchronous replication capabilities. In much the same way a local RMAN backup, if consistent, can be used directly, or with archived redo logs if not consistent, the remote replica can quickly be brought online at the remote site if need be. Writes on the ZFS Storage Appliance are handled atomically, if the whole write cannot be completed, the write is not acknowledged and will be resent. Replication is also handled atomically to ensure that both sides of the replica are exactly the same. Tape Backup A time honored way to move data offsite has been backup to tape. The removable nature of tape media makes it a desirable backup destination. This solution, however, requires a mechanism to manage a media manager such as Oracle Secure Backup as the diagram below shows. It is also desirable to allocate one of the 10Gb Ethernet channels available on the Oracle Database Appliance to this Media Server as it will make backups significantly faster. Oracle Secure Backup is a media manager that provides reliable and secure data protection through file system backup to tape. All major tape drives and tape libraries in SAN, Gigabit Ethernet, and SCSI environments are supported. The Oracle Secure Backup Tape (SBT) interface enables you to use Recovery Manager (RMAN) to backup and restore Oracle Database files to and from tape. If encryption has not been used earlier in the process, either at the database or through RMAN, the tape drive is a fast and practical way to encrypt data cartridges before they are moved offsite. 5

6 Tape is a cost effective way to provide backup, but neither backup or restore is fast. The greatest advantage to using tape, however, is that it does not require any power to store data for extended periods of time. In this sense it is a great medium for archival. The best way to achieve fast backups and fast restores and long term archival of data for, say, regulatory compliance, is by combining disk and tape as depicted in the illustration below. This approach contains the impact on the production database to the hot, or cold, RMAN backup. Copy to tape occurs completely offline, eliminating the need to think in terms of backup window while tapes are written. Combining two of these approaches, remote replication from the Storage Appliance and offline backup to tape, is considered a best practice for meeting Recovery Time Objectives, Disaster Recovery and Long Term Archival requirements in a single, simple, architecture. This arrangement, depicted below, accommodates a warm site DR scenario, it is an easy step to imagine a hot site scenario where active, independent, databases on either side uses the second site for DR purposes. Some sites wi An alternative to this approach is to use Oracle s Data Guard to replicate to a second Database Appliance at the remote site. This approach provides a recovery time advantage in the case of a catastrophe at the primary site. Some implementations of the Oracle Database Appliance will 6

7 require Disaster Recovery in the form of an active database at both the primary site and the secondary site, and for this purpose Active Data Guard would meet the need. Any of the backup mechanisms described previously will complement a Data Guurd, or Active Data Guard implementation to add backup to the high availablitity that Data Guard provides. Additional Advantages of Using the ZFS Storage Appliance ZFSSA Data Services for Database Duplication Frequently, it is a challenge to provide current copies of databases to other environments, such as Test, Development or for Reporting purposes. Using the ZFS Storage Appliance as a backup target for RMAN makes provisioning to these environments fast and easy. The process calls for creating a writeable snapshot, called a clone, of the backup for each environment required. Clones are an optional feature of the ZFS Storage Appliance. The clone is then provisioned to the environment that is to be enabled. The process is simple, the Test Environment, for example, would need Oracle Database installed. A consistent backup would be cloned and the test server would be given access to storage device holding the clone. The database can then be opened. 7

8 Storage Consolidation on ZFSSA Perhaps the most direct way to increase the economic benefit of adding a ZFS Storage Appliance to your environment is to consolidate other workload to the box beside the backup workload. The ability of the Storage Appliance to handle mixed workloads is founded on Hybrid Storage Pools; a mix of Dynamic RAM, Solid State Disk and Large Capacity disk to provide the best characteristics of each, while overcoming the inherent weaknesses of each. The ZFS Storage Appliance provides a number of interfaces, such as NFS, CIFS, Fibre Channel, iscsi, InfiniBand, HTTP, FTP, WebDAV, among others. All interface licenses are included with the box, some, such as Fibre Channel, may require that the appropriate Host Bus Adapter be added. The ability to handle a workload with varying I/O characteristics, such as small writes and reads at a high transaction rate, mixed with streaming applications that require higher bandwidth, such as backup, combined with virtually any interface desired, makes the box a perfect consolidation platform. Of course, any of the previously mentioned techniques for data protection and disaster recovery can be used for the additional workload. 8

9 Comparing Backup Destination Options The following table summarizes the three target backup destinations and the associated attributes. Backup to Internal Storage (FRA) Backup to ZFSSA (RMAN) Backup to Tape (RMAN and OSB) Replicate to Remote ODA (ADG) Primarily protect against Logical corruption Protect against Physical and Logical Corruption Protection against Physical, Logical corruption and sitefailure. Primarily protection against physical corruption and site failure Fastest data protection -Immediate Backup & Restore Fastest and Most Flexible External Backup Option Advance ZFSSA Data Services Most economical Fastest in site failures Short-term protection of fresh data Short and medium term protection Focus on long-term protection, archival of multiple instances of data Short-term protection of fresh data and transactions Best efficiency and reduced costs - no 3rd party costs, implementation or integration risks Datacenter best practices by Oracle on Oracle easy to implement and manage Automating the Backup Process Oracle Enterprise Manager Database Control or Grid Control Oracle Enterprise Manager is a GUI-based management tool that provides an easy way to schedule and run backups. The screen grab image on the next page shows that the backup functionality is accessed under the Availability tab. 9

10 You first create your backup settings where you specify Device specifics, Backup Set information and Backup Policy information. The next image shows the Device screen you receive when you select Backup Settings. It allows you to specify whether you are backing up to disk (specifying a location) or to tape and whether the backup set is compressed. 10

11 The Backup Set screen asks for information such as what compression algorithm to be used, and how many copies of backup files are required. The Policy screen collects information about the policies affecting the backup such as whether the control file and spfile should be automatically backed up, the retention policy for backups, and whether any tablespaces should be excluded from the backup. Scripting Backup and Recovery Operations Some DBAs like to have greater control over how the backup is performed and as such prefer to use a command line interface to perform the backup. Again, the tool used to perform this work is RMAN. The following is an example script showing how a backup and recovery can be run with the backup destination to a File System/NAS server. Backup example to FileSystem/NAS destination: $ORACLE_HOME/bin/rman nocatalog target / log=$log_location/full_db_bk_`date +'%Y%m%d%H%M%S'`.log RMAN> run { CONFIGURE CONTROLFILE AUTOBACKUP ON; CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '$BACKUP_DEST/%F'; allocate channel c1 device type disk format '$BACKUP_DEST/db_%U'; backup database plus archivelog not backed up delete all input; } Recovery example: $ORACLE_HOME/bin/rman nocatalog target / log=$log_location/recv_db_`date +'%Y%m%d%H%M%S'` using $DB_ID RMAN> run {startup nomount; set controlfile autobackup format for device type disk to '$BACKUP_DEST/%F'; restore spfile from autobackup; startup force nomount; restore controlfile from autobackup; alter database mount; restore database; recover database; } Environment Settings For NAS best practice recommendations, consult the following note in My Oracle Support (MOS): 11

12 Conclusion The Oracle Database Appliance uses the same backup and recovery capabilities used for Oracle databases running in non-appliance environments. DBAs have the same destination options, Flash Recovery Areas on disk, File System/NAS, and tape. Backup and Recovery can be accomplished using the GUI-based Oracle Enterprise Manager or from a command line. All these operations can be automated as well. The significant advantage the Oracle Database Appliance offers for backup and recovery is its multiple, built-in networking options. With both 1GbE and 10GbE networking interfaces, DBAs have options with respect to which channel they use to perform backups. By dedicating one of the built-in 10GbE channels to the backup operation, The Oracle Database Appliance can make backups faster and easier to perform. Combining the Oracle Database Appliance with the ZFS Storage Appliance provides a number of advantages: Preserving finite disk space on the Database Appliance Protection against system failure Enabling Disaster Recovery with remote replication Providing long term archival when combined with the use of tape, Provisioning data to other environments, such as test & development Economic benefit through consolidating workloads. 12

13 Oralce Database Appliance Backup and Reocvery October 2011 Oracle Corporation World Headquarters 500 Oracle Parkway Redwood Shores, CA U.S.A. Worldwide Inquiries: Phone: Fax: Copyright 2011, Oracle and/or its affiliates. All rights reserved. This document is provided for information purposes only and the contents hereof are subject to change without notice. This document is not warranted to be error-free, nor subject to any other warranties or conditions, whether expressed orally or implied in law, including implied warranties and conditions of merchantability or fitness for a particular purpose. We specifically disclaim any liability with respect to this document and no contractual obligations are formed either directly or indirectly by this document. This document may not be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without our prior written permission. Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners. Intel and Intel Xeon are trademarks or registered trademarks of Intel Corporation. All SPARC trademarks are used under license and are trademarks or registered trademarks of SPARC International, Inc. AMD, Opteron, the AMD logo, and the AMD Opteron logo are trademarks or registered trademarks of Advanced Micro Devices. UNIX is a registered trademark licensed through X/Open Company, Ltd oracle.com