Re: Oracle OBACKUP
Date: Fri, 21 Oct 94 04:07:30 GMT
Message-ID: <1994Oct21.040730.6486_at_enterprise.rdd.lmsc.lockheed.com>
In article <781734273snz_at_tomcooke.demon.co.uk> tom_at_tomcooke.demon.co.uk writes:
>In article <89B3527.03890014D1.uuout_at_compudata.com> > barry.roomberg_at_compudata.com "BARRY ROOMBERG" writes: > >> -> We're looking for more information on OBACKUP for the HP9000. What >> -> does it do? Our backup software (Legato Networker) requires it for >> -> their database backup module so we can backup and restore tables >> -> without taking them offline. We're curious about the cost of the >> -> OBACKUP product. Please reply by mail and I will summarize if there >> -> is interest in the subject. >> >> Huh? What's wrong with using normal Oracle backup procedure, >> ie: ALTER TABLESPACE BLAH BEGIN BACKUP, do your DD, >> ALTER TABLESSPACE BLAH END BACKUP, force a bunch of log switches, >> archive'em off, and you're done! >> >I'd be interested in the summary, we are about to talk to Oracle about >OBACKUP for our about-to-be-implemented big d'base. As far as I know, >the thing about OBACKUP is the way it can parallelise operations that >you'd normally do using the `normal' warm backup procedure. >Hint; back up your control file before AND after a warm backup. >-- >Tom Cooke tom_at_tomcooke.demon.co.uk +44 (0)1782 748027 >North Staffordshire Hospital Computer Centre, Stoke-on-Trent, Staffordshire, UK
I got this faq from Legato, It has some good information on obackup.
Dave Erwin
Lockheed Missiles & Space Company
email: erwin_at_lmsc.lockheed.com
obackup Frequently-Asked Questions with Answers Copyright (c) 1994, Legato Systems, Inc. All rights reserved.
Last Update: August 29, 1994
This document contains answers to frequently-asked questions about the Oracle Parallel Backup/Restore Utility, also known as obackup. Note that this document is authored by Legato Systems, Inc. and is not an official statement by Oracle Corp. or Legato Systems, Inc. Information contained herein is believed to be accurate at the time of writing, but this is not guaranteed. For complete information, please contact Oracle and/or your storage-management vendor.
Table of Contents
1.0 General obackup Questions 1.1 What exactly is obackup? 1.2 What are the salient features of obackup? 1.3 Where can I get obackup? 1.4 How much does obackup cost? 1.5 Can I just use tar(1) or dump(1) with obackup? 2.0 Terminology 2.1 What's the target database?
2.2 What is the external database / backup catalog? 2.3 What's the difference between a full and a partial backup?
3.0 obackup and ORACLE Databases 3.1 Can obackup back up online databases? 3.2 What about online redo logs, archived redo logs, and the database
control file?
3.3 What about databases that reside on UNIX raw disk partitions or
logical volume managers?
3.4 Do I need to be running ORACLE 7.1 to use obackup? 3.5 How does obackup quiesce the database during online backups? 3.6 How is the database shut down or restarted when I do scheduled
full backups?
4.0 obackup and Legato NetWorker
4.1 Do I need a separate backup device for each unit of obackup
parallelism I intend to use? (The Oracle documentation says this.)
5.0 The External Database / Backup Catalog 5.1 Do I have to create the external database myself? 5.2 Is the external database separate from the databases I'm
interested in backing up?
5.3 Why is housing the backup catalog in a target database strongly
discouraged?
5.4 I have to install an entire other database just to run this
product? Won't that take a lot of disk space? 5.5 How do I back up the external database?
6.0 Performance
6.1 What kind of performance can I expect from obackup?
7.0 Other Sources of Information
7.1 What additional documentation on obackup is available?
1.0 General obackup Questions
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1.1 What exactly is obackup?
obackup is a product that allows ORACLE7 database data to be sent to and managed by third-party storage management products such as Legato NetWorker. Oracle provides half of obackup; the storage management vendor provides the other half. Neither half is useful in isolation. You must use them together.
Note that the real name of the Oracle product is the "Oracle Parallel Backup/Restore Utility". Most people just call it "obackup", after one of the executables in the product.
1.2 What are the salient features of obackup?
Online ("hot") backup: Database backups can be taken while the database is online.
Parallel capabilities: Database entities can be backed up and restored in parallel, potentially decreasing time to backup or restore and increasing hardware utilization.
Integration: Like normal filesystem data, database data can be managed via sophisticated third-party storage management tools like Legato NetWorker.
Complete backups: Full backups include online redo logs and the database control file.
Interruptibility: Backup jobs can be interrupted and later restarted where they left off.
Safety: obackup performs database block-level integrity checking at recover time.
Flexibility: Database entities can be remapped at recover time to an alternate location, and can be recovered to a given point-in-time, etc.
Reports: obackup can generate reports of database backup history and target database configuration.
Conceptualization: DBAs can deal with logical entities (like tablespaces) rather than physical ones (database files). But for maximum tunability, backups can be scheduled down to the database file level, if desired.
1.3 Where can I get obackup?
You must get part of obackup from Oracle, and another part from a third-party storage management vendor like Legato. The Oracle piece is bundled with the ORACLE 7.1 RDBMS (contact Oracle for details). It may also be available from Oracle as a separately-orderable product.
In Legato's case, the name of the software you need to get is the "Legato NetWorker Oracle Database Module".
1.4 How much does obackup cost?
The Oracle piece is bundled with ORACLE 7.1 at no extra charge. (It may also be separately orderable; contact Oracle for details.) Storage management vendors' prices will vary, of course. Call your Legato reseller for details on the pricing of the Legato software.
1.5 Can I just use tar(1) or dump(1) with obackup?
No. You must use a product that has specifically been designed for use with obackup.
2.0 Terminology
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2.1 What's the target database?
The target database is the ORACLE7 RDBMS you have targeted for protection. A single obackup installation can manage multiple target databases.
2.2 What is the external database / backup catalog?
The external database is a separate ORACLE 7.1 instance that houses something called the backup catalog. The backup catalog is used only by obackup (and its associated tools) to track database configuration information and backup history, amongst other things. For example, you can use the backup catalog to generate customized backup history and database configuration reports. If you are familiar with NetWorker, the backup catalog is analogous to NetWorker's file and media indexes.
Most sites will have only a single external database, even if there are multiple target databases. obackup can use a single external database to manage multiple target databases.
The external database is covered in more depth in another section of this document.
2.3 What's the difference between a full and a partial backup?
Oracle defines a full database backup as the backup of a database, all its data files, the database control file, and the online redo logs for the database. By necessity, full backups require the database to be shut down. If you have stringent uptime requirements, you may not be able to perform full backups.
Partial database backups back up only selected parts of the database. Online redo logs cannot be backed up at all via a partial backup. To backup the online redo logs, the database must be down; this is a limitation in the ORACLE RDBMS. The database can be online or offline during a partial backup.
3.0 obackup and ORACLE Databases
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3.1 Can obackup back up online databases?
Yes. Online ("hot") backup is one of the major features of the product.
3.2 What about online redo logs, archived redo logs, and the database
control file?
obackup can back up online redo logs and the database control file. Note that the database must be offline to backup online redo logs; this is a limitation in the ORACLE RDBMS.
obackup does not currently handle archived redo logs. As of this writing, Oracle has said that archived redo log support will be added in the next revision of obackup. Contact Oracle for more details.
In the meantime, you can use normal filesystem backup and recovery methods (such as NetWorker's save(1) and recover(1) programs) to manage your archived redo logs.
3.3 What about databases that reside on UNIX raw disk partitions or
logical volume managers?
obackup can handle databases that reside on regular UNIX filesystems, UNIX raw disk partitions, or logical volume managers with equal ease. Administering them via obackup is the same.
3.4 Do I need to be running ORACLE 7.1 to use obackup?
No. obackup will work just fine with ORACLE 7.0.12 and later, although the external database (a separate database containing target database configuration information, backup history, etc.) must be 7.1. obackup is not supported on versions of ORACLE prior to 7.0.12, including ORACLE6.
3.5 How does obackup quiesce the database during online backups?
obackup uses the ALTER TABLESPACE BEGIN BACKUP command before backing up the database entity to ensure it is in a consistent state. After the backup has completed, obackup issues an ALTER TABLESPACE END BACKUP command.
3.6 How is the database shut down or restarted when I do scheduled
full backups?
obackup in and of itself does not provide a way to shut down or restart the target database as would be necessary for an offline full. However, Legato's product does provide an easy way to shutdown and restart the database, so this is the way to go with the Legato product. (Legato's piece does quite a bit more as well. For example, you can have an arbitrary series of commands run both pre- and post-backup, and set environmental variables like ORACLE_HOME for obackup, etc.)
4.0 obackup and Legato NetWorker
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4.1 Do I need a separate backup device for each unit of obackup
parallelism I intend to use? (The Oracle documentation says this.)
No. The Oracle documentation is wrong. (Specifically, the Oracle Parallel Backup/Restore Utility Administrator's Guide says this. Other Oracle documents may say it as well.) Legato NetWorker--unlike many other storage management products-can multiplex data streams at the drive. So you can send multiple data streams to a single drive, if you wish. Depending on your configuration, this may increase performance and backup media utilization-perhaps at a lower cost.
5.0 The External Database / Backup Catalog
5.1 Do I have to create the external database myself?
Some ports of obackup-notably the Solaris port-will automatically create the external database for you when you install obackup. On other architectures (such as AIX and SCO, perhaps), you must create the external database manually yourself.
5.2 Is the external database separate from the databases I'm
interested in backing up?
It should be. Although some obackup releases will theoretically allow you to house the backup catalog in a target database, this is strongly discouraged.
5.3 Why is housing the backup catalog in a target database strongly
discouraged?
Because the external database is needed for recovery. So if your target database is damaged or destroyed, so is your backup catalog, and recovery will be difficult at best.
5.4 I have to install an entire other database just to run this
product? Won't that take a lot of disk space?
Not really. You do have to install another database (note that on some architectures, the installation process will automatically create the external database for you). It shouldn't take up much space, though. Oracle generally recommends the external database be on the order of 20 megabytes in size.
5.5 How do I back up the external database?
Unfortunately, there isn't any way to back up the external database via obackup itself; that would present a bootstrapping problem. Currently, the best way to back up the external database is to shut it down (not normally a big deal, since it's a separate database) and back it up using normal filesystem backup methods, such as Legato's save(1) program. When the backup is complete, you can restart the external database.
6.0 Performance
----------------------------------------------------------------------
6.1 What kind of performance can I expect from obackup?
Performance varies widely depending on hardware (number and types of CPU, disk configuration, SCSI bus types and configuration, backup media type, etc.) and software configurations, so predicting performance is extremely difficult.
In Legato's labs, we have achieved backup rates exceeding 17 gigabytes per hour and restore rates exceeding 14 gigabytes per hour on a 12-processor Sun SPARCcenter 2000. (Precise details of the test are available from Legato.) Some of Legato's OEMs (for example, Sequent Computer Corporation, makers of ptx/BACKUP, which is based on Legato NetWorker) have reported even higher rates using different configurations. Your mileage may vary.
7.0 Other Sources of Information
----------------------------------------------------------------------
7.1 What additional documentation on obackup is available?
From Legato:
"Protecting Oracle Databases with Legato NetWorker", Legato part number 8569. This is a white paper on the protection of ORACLE7 databases, highlighting Legato NetWorker as the storage management solution of choice.
"Legato NetWorker Oracle Database Module Administrator's Guide", Legato part number 22-1689-01 and included with Legato's Oracle Database Module. This is the definitive reference for the Legato software; also includes some tips about obackup that are generally useful.
From Oracle:
"Oracle Parallel Backup/Restore Utility Administrator's Guide", part number A12994-1, and included with obackup. The definitive reference for the Oracle software.
"Oracle7 for [System Name] Parallel Backup/Restore Utility Installation and Configuration Guide"; part number varies. An architecture-specific reference for the installation and configuration of the obackup utility.
"Oracle Parallel Backup/Restore Utility"; part number unknown. An Oracle white paper describing the high-level features of the utility. Received on Fri Oct 21 1994 - 05:07:30 CET