VERITAS Rapid Recovery for Microsoft SQL Server

Transcription

1 VERITAS Rapid Recovery for Microsoft SQL Server RECOVERING MICROSOFT SQL SERVER DATABASES WITH VERITAS DATABASE EDITION FOR MICROSOFT SQL SERVER AND VERITAS NETBACKUP 1

2 TABLE OF CONTENTS Table of Contents...2 Overview...3 VERITAS Database Edition for Microsoft SQL Server...4 Creating Dynamic Disk Groups and Volumes...4 VERITAS FlashSnap...5 Point-in-Time Recovery...5 Point-of-Failure Recovery...5 On-Host and Off-Host Volume Snapshot Creation and Backup Capability...5 VERITAS NetBackup...5 Quick Recovery Procedures...6 Point-of-Failure Recovery from a Quick Recovery Image...6 Integration of NetBackup and Flashsnap Quick Recovery...6 Off-Host Backup and Recovery Operations...7 Creating a NetBackup Policy for an Offline (Off-Host) Backup...7 Performing Database Snapshots and Off-Host Backups...7 Point-In-Time Recovery From An Off-Host Backup...7 Point-of-Failure Recovery from an off-host backup...8 Performance and Scalability...9 Summary

3 OVERVIEW Organizations today depend on their computing infrastructure to fulfill their daily transactions and to meet service level agreements. As an important component in a data center, SQL databases must be continuously available and safe from failures. As more and more demands for continuous access of mission-critical data are placed on Microsoft SQL Server environments, the importance of keeping them up and running and highly available has become even more crucial. SQL Server administrators need the ability to recover from SQL data corruption problems. Just being able to recover is not enough. Administrators need the ability to recover as quickly as possible to minimize downtime. Restoring from backup tapes takes hours at best, and only provides the ability to restore to the point in time of the last backup. Transactions that occurred after that point are lost. Protecting data with a well-designed backup strategy is essential in SQL environments; however, the backup process places additional requirements on the SQL server and can negatively impact system performance. Administrators need the ability to perform off-host backups of the SQL Server environment, virtually eliminating a performance impact and allowing the SQL Server to remain dedicated to SQL processing. This white paper describes how VERITAS solutions can be used to address the rapid recovery of Microsoft SQL server databases. 3

4 VERITAS Rapid Recovery Solution The VERITAS Rapid Recovery of Microsoft SQL Server Solution is an integration of industry-leading VERITAS technologies that facilitate creation and deployment of disk image copies of SQL Server databases for quickly recovering from catastrophic failures. It further provides for efficient off-host backups of SQL Server databases, freeing production resources for production tasks. The Rapid Recovery Solution is an integration of the following VERITAS products and components: VERITAS Database Edition for Microsoft SQL Server VERITAS NetBackup DataCenter for Windows VERITAS Database Edition for Microsoft SQL Server is an integrated suite of industry-leading VERITAS storage management technologies engineered specifically to improve manageability, increase availability, and ensure quick recovery of Microsoft SQL Server deployments. The VERITAS Database Edition for Microsoft SQL Server, referred to in this document as VERITAS Database Edition, provides SQL administrators with the ability to create mirror-image copies and backup databases with minimal disruption to the SQL services or users, as well as rapidly recover SQL data in the event of corruption or loss. The feature of VERITAS Database Edition that enables this is the FlashSnap Utility. The VERITAS Database Edition FlashSnap Utility has two components. The FlashSnap Backup and Recovery feature provides the ability to create split-mirror snapshots that can be used off-host for operations such as backup or data mining. This virtually eliminates the performance impact of backup operations or business intelligence work on the production SQL server, allows the backup server to backup the snapshot at local fibre channel speeds, and reduces the LAN data traffic impact of online backups. The FlashSnap Quick Recovery feature allows the creation of multiple on-host split-mirror snapshots for quick recovery of SQL Server databases. These snapshots can be used to restore corrupted databases directly from disk reducing the time needed to bring SQL Server back online after a failure. NetBackup DataCenter for Windows is the backup mechanism that moves the Microsoft SQL Server data from disk to tape. This backup solution provides the ability to recover a Microsoft SQL Server to the original system or to a different host. VERITAS NetBackup DataCenter delivers mainframe-class data protection for the largest enterprise environments, especially for corporate data centers. Organizations can manage all aspects of backup and recovery using intuitive, graphical user interfaces, allowing consistent backup policies to be enforced across the enterprise. VERITAS NetBackup DataCenter provides the most advanced media management available, including such capabilities as tape labeling, tape media pool creation, device sharing, media/device reporting and bar code support. VERITAS NetBackup DataCenter also provides optional database and application aware backup and recovery solutions for Microsoft SQL Server. VERITAS DATABASE EDITION FOR MICROSOFT SQL SERVER Creating Dynamic Disk Groups and Volumes The Database Edition incorporates Volume Manager technology, which provides the ability to create volumes for data storage. These volumes can be created using different RAID configurations. Once created, these volumes can be assigned a drive letter or assigned to a specific mount point. Volumes are organized by disk groups. Disk groups can be deported from one server and imported onto another server if the disk storage is shared between systems via SCSI or SAN. A volume cannot be shared between disk groups, but it may be removed from one disk group and inserted into another disk group with the Volume Manager Disk Group Split and Join functionality. This functionality is leveraged with VERITAS Database Edition and the VERITAS Rapid Recovery solution 4

5 VERITAS FlashSnap VERITAS FlashSnap allows you to create independently addressable multi-purpose volumes (MPVs) that are copies or mirrors of the volumes on your server. When these MPVs are moved to a remote server, they can be used for backup and other activities, such as uploading or updating data warehouses or performing application testing while business continues. To greatly reduce the resynchronization time and performance impact on the server when the volume snapshot is reattached, FastResync technology synchronizes only the changes that occurred while the volume snapshots were split. These point-in-time copies can also serve as on-disk backup images for protecting mission-critical data. FlashSnap works with a wide range of disk subsystems, delivering a powerful and flexible solution that frees you from hardware and application restrictions. Point-in-Time Recovery Point-in-Time Recovery is the process of recovering a SQL database to the point in time of any successful snapshot or backup. Point-of-Failure Recovery The Point of Failure Recovery feature provides the ability to fully restore a database to a point immediately before an interruption in service. This is accomplished by restoring the database to the last snapshot backup prior to the interruption and then, automatically replaying the transaction logs created subsequent to the backup and prior to the interruption. On-Host and Off-Host Volume Snapshot Creation and Backup Capability By using the VERITAS Database Edition FlashSnap Utility, you can create volume snapshots of Microsoft SQL Server databases and transaction logs while they are online. Once these volume snapshots are created, you can backup the data locally or migrate the snapshot volumes to another server, such as a NetBackup Media Server. Once the volume snapshot is imported onto another server, backups can be performed. Afterwards, the volumes can be returned to the original server and re-joined to the mirror set. The FlashSnap Utility automates the entire process. VERITAS NETBACKUP The NetBackup server provides the ability to backup specific Microsoft SQL Server databases and transaction logs. This server contains all of the backup metadata necessary to restore files to the original SQL Server system or to an alternate Microsoft SQL server. The Rapid Recovery solution involves the integration of NetBackup backups with Database Edition Quick Recovery snapshot images. Database snapshots are taken individually, thus separate scripts and initialization files are required for each database on a server for which this solution is applied. The need for separate snapshot scripts implies a need for separate NetBackup policies for each database. Thus, the Rapid Recovery solution requires that a separate NetBackup Policy be created for each Microsoft SQL Server database The NetBackup Policy is created from the NetBackup Master Server. The NetBackup Master Server manages the scheduling, frequency, clients, and files that are determined necessary to backup. The NetBackup Master Server also manages the metadata catalog database, which contains the information necessary to locate and restore the client data. 5

6 QUICK RECOVERY PROCEDURES The FlashSnap Quick Recovery feature enables the administrator to quickly (within minutes) return a damaged or lost SQL Server database to production use by orchestrating the restoration of a snapshot mirror image of the database and playback of transaction logs up to the point of failure. The entire process is controlled by the FlashSnap Utility so that the possibility of errors is minimized. The utility makes extensive checks to ensure that the Quick Recovery process is possible, has been correctly specified, and will succeed before it begins the actual recovery operation. If problems or errors are detected, the FlashSnap Utility will attempt to return the snapshot images to their original state and location so that another Quick Recovery operation can be attempted. FlashSnap Quick Recovery creates a copy of production SQL database and transaction log files on VERITAS Volume Manager dynamic volumes such that, in case of database corruption, the SQL database administrator can recover the application data quickly using the copy. The FlashSnap Quick Recovery utility makes a snapshot copy of production SQL databases and mounts them on the SQL Server host for quick access. If database corruption should occur, the FlashSnap Recovery utility can restore the production database from the local snapshot copy. The user can make multiple snapshot copies of the production SQL databases. The user has the option to refresh existing copies, that is, resynchronize copies with the current application data on the production volumes. Copies can be deleted once they are no longer needed. POINT-OF-FAILURE RECOVERY FROM A QUICK RECOVERY IMAGE Point-of-Failure recovery is provided by the VERITAS Database Edition FlashSnap Utility. Point-of-Failure recovery provides the ability to fully restore a SQL database to a point immediately before a failure. This form of recovery is accomplished by using NetBackup to restore the full backup of a known good point-in-time image, and then using the FlashSnap Recovery utility to coordinate replaying the transaction logs created subsequent to the backup and prior to the failure. Note that recoveries can only be done to the point of the last backed up transaction log. In order to take full advantage of this feature, transaction logs should be periodically backed up. INTEGRATION OF NETBACKUP AND FLASHSNAP QUICK RECOVERY By combining NetBackup online backups and VERITAS Database Edition FlashSnap Quick Recovery operations, the administrator can have reliable and proven NetBackup backup operations of SQL Server databases coordinated with creation and updates of FlashSnap disk images of the SQL databases and transaction logs, which can be used to very quickly recover from disaster or data loss situations. The disk images can also be deported to other servers for data mining or business intelligence operations. VERITAS recommends coordinating the updates of database snapshots with using NetBackup to run full online backups of the production SQL Server database. Coordination of these operations is necessary because of the goal of Quick Recovery. Full online backups may prune back transaction logs, and can affect Quick Recovery. To accomplish Quick Recovery, all applicable transaction logs must be available for the FlashSnap Quick Recovery utility. A snapshot taken by the FlashSnap Utility contains the database plus all transaction logs available at that point in time, thus snapshots should be performed after a full backup of the database is performed so that the logs with the snapshot are not invalidated. 6

7 OFF-HOST BACKUP AND RECOVERY OPERATIONS This solution provides the ability to backup a Microsoft SQL database to an alternate host. This host is classified as a backup server. This capability increases accuracy and efficiency and the verification process guarantees data integrity. Automated off-host backup and recovery keeps the SQL server dedicated to SQL processing and minimizes the impact to SQL and system performance. This solution requires disks that are shared between the Microsoft SQL Server and the NetBackup Media Server. The FlashSnap Backup and Recovery feature coordinates and executes the operations that back up SQL data to tape or other media and restore SQL data from the backup media. The FlashSnap Backup feature creates pointin-time images of the SQL data and coordinates the process of backing up the images to tape or other media. If SQL databases or transaction log files are corrupted, the FlashSnap Recovery feature can restore them from the backup media. CREATING A NETBACKUP POLICY FOR AN OFFLINE (OFF-HOST) BACKUP A NetBackup policy is required to control offline, off-host backups in coordination with the Database Edition FlashSnap Utility. The policy is used to control the schedule for, and orchestrate the operation of the Database Edition FlashSnap Utility so that offline, off-host backups can be controlled and coordinated by the NetBackup master console. PERFORMING DATABASE SNAPSHOTS AND OFF-HOST BACKUPS Microsoft SQL Server provides application programming interfaces (APIs) that enable the FlashSnap Utility to integrate with the SQL Server for snapshot backups. These APIs are engineered to provide maximum reliability and performance. The SQL Server Virtual Backup Device Interface (VDI) provides the highest online backup throughput with minimal degradation to the transaction workload, as well as the fastest possible restore times. It enables the FlashSnap Utility to achieve similar performance characteristics to the SQL Server native backup/restore. A snapshot of a Microsoft SQL Server database taken with the VERITAS FlashSnap Utility is a copy of data and log files at a single point in time. The snapshot copies that are created are point-in-time copies of the SQL database using the VERITAS FlashSnap technology in coordination with the SQL Snapshot API, Virtual Device Interface for Backup (VDI). A full SQL database snapshot captures all data and log files and is equivalent to a full SQL database backup. The VERITAS Database Edition FlashSnap Utility coordinates with the SQL Server to do the snapshot without damage to the SQL database. The database remains available; reads are unaffected and writes are only suspended momentarily. To perform off-host backups, the VERITAS Database Edition FlashSnap Utility automates the process of taking a split-mirror image copy of the production SQL Server database, breaking off the mirror, deporting the mirror copy from the production server, importing the mirror copy to the NetBackup server, running the NetBackup backup operation, deporting the mirror copy from the NetBackup server, re-importing it to the production server, and finally re-joining and resynchronizing the mirror set. POINT-IN-TIME RECOVERY FROM AN OFF-HOST BACKUP The FlashSnap Backup and Recovery feature provides the ability to restore a SQL database that has been corrupted due to a hardware or software error. FlashSnap Recovery restores on a per database basis and all the SQL database and transaction log files in the database are restored by the recovery process. The FlashSnap Recovery process uses the existing split-mirror snapshots that are used for the FlashSnap Backup process. As discussed previously, these snapshots are point-in-time copies of the SQL database and 7

8 transaction logs. The Point-in-Time Recovery from one of these snapshots is thus a recovery operation that restores the database and transaction logs to the exact point in time of the snapshot. The administrator can recover to Point-of-Failure. POINT-OF-FAILURE RECOVERY FROM AN OFF-HOST BACKUP Point-of-Failure recovery from an off-host backup is procedurally identical to point-of-failure recovery from a quick recovery image discussed earlier in this paper. 8

9 PERFORMANCE AND SCALABILITY Consistent snapshot images of Microsoft SQL Server databases and transaction logs may be made using the VERITAS Database Edition FlashSnap Utilities. The FlashSnap Utilities allow the creation of a snapshot of an SQL database without taking it off-line, by communicating with SQL Server via the Virtual Device Interface (VDI). Use of this interface allows the FlashSnap Utilities to temporarily quiesce operations, perform the snapshot, and resume operations cleanly. The clean snapshot feature of the VERITAS Database Edition FlashSnap Utilities allows the production databases to continue to operate during snapshots without interruption. VERITAS recommends the FlashSnap Utilities be run in conjunction with online backup operations so as to coordinate the creation and updating of snapshot images with the online backup and maintenance of SQL databases and transaction logs. In consideration of sizing and planning the integration of FlashSnap Utilities operations with regular backups, VERITAS has tested the clean snapshot capability of the VERITAS Database Edition FlashSnap Utilities in a number of different SQL Server configurations using a variety of database sizes, transaction log sizes. Testing was performed on commonly available systems and storage hardware. For the first set of test scenarios, FlashSnap Backup and Recovery (off-host off-line) backup operations were performed, which include: for Backup operations, performing a snapshot, volume deport, the actual off-host backup operation, volume import, and re-sync. for Recovery operations, performing an off-host recovery operation, volume import, database mount and (in the case of point-of-failure recovery) transaction log playback. Results from these tests, including timing information, are summarized in the following tables. Table 1: Snapshot & Off-host backup timings DB size (GB) Log size (GB) Snapshot create & deport NetBackup processing Snapshot import & resync Total :33:16 00:39:00 00:16:00 01:28: :30:00 01:15:00 00:25:00 03:10: :19:00 01:51:00 00:40:00 04:55:00 Table 2: Off-host Recovery operation timings DB size (GB) Log size (GB) Prepare/send volume to Recovery Server NetBackup processing Import & resync to SQL Server Total :13:53 00:58:00 00:22:00 01:33: :20:34 02:12:00 01:28:00 04:10: :20:00 02:25:00 02:23:00 05:08:00 Testing of the FlashSnap Utilities also included exercising the Quick Recovery capabilities, which included: Quick Recovery image creation and updates Recovery to point-of-failure using Quick Recovery images 9

10 In all combinations, the operations were verified to be successful and that the databases were properly recovered. In order to assist SQL Administrators with online backup and FlashSnap Utility integration planning, timing information was also gathered for each of the snapshot and recovery operations. This data can be combined with known data for currently used online backup operations to establish integration guidelines. Timings are included in the table below: Table 3: Quick Recovery Create, Update and Restore timings DB size (GB) Log size (GB) QR image QR image QR restore time creation time update time :25:01 00:03: :04:46 00:16: :31: :03: :04:47 00:07: :53: :03: :05:24 -- Snapshot creation timings reflect the time required to create a full mirror image of the database and transaction logs, which is subsequently broken off, for deportation to a backup server, or for storage as a standby image that may be used for Quick Recovery operations described earlier in this paper. The image creation time is a onetime cost incurred when the image is first prepared. As shown in the above table, snapshot images may be later updated with the FlashSnap Utilities an order of magnitude more quickly. The combined mode of online backups and snapshot image updates is the recommended operational mode. 10

11 SUMMARY Why The VERITAS Solution for Rapid Recovery of Microsoft SQL Server This white paper discussed the underlying values found when using the VERITAS solution to support Microsoft SQL Server. A comprehensive rapid recovery solution for SQL Server demands the following critical requirements: A solid storage management and backup foundation with industry-leading technologies Advanced volume-level snapshot capabilities The ability to quickly recover a SQL database to the point of any successful snapshot or backup or fully restore a SQL database to a point immediately before a failure The ability to maximize online processing by performing off-host backups with verified snapshots which guarantee data integrity Only VERITAS can deliver all of these critical rapid recovery capabilities to support even the most demanding and complex SQL Server environment any only VERITAS can offer the network of customer support services. VERITAS reputation for solid, dependable solutions is what gives demanding customers the confidence to adopt new technologies and deploy complex solutions. A VERITAS rapid recovery solution isn t just a set of products, it s a company with the technology, vision, products, skills and resources needed to poer your SQL Server solutions in today s highly competitive economy. 11

12 VERITAS Software Corporation Corporate Headquarters 350 Ellis Street Mountain View, CA or For additional information about VERITAS Software, its products, or the location of an office near you, please call our corporate headquarters or visit our Web site at Copyright 2002 VERITAS Software Corporation. All rights reserved. VERITAS, VERITAS Software, the VERITAS logo, and all other VERITAS product names and slogans are trademarks or registered trademarks of VERITAS Software Corporation in the US and/or other countries. Other product names and/or slogans mentioned herein may be trademarks or June