Backup and Recovery

1. Section 3 : Business Continuity Backup and Recovery Chapter 12

2. Chapter Objective Upon completion of this chapter, you will be able to: • Describe Backup/Recovery considerations • Describe Backup/Recovery operations • Describe Backup topologies • Describe backup technologies

3. Lesson: Backup/Recovery Overview Upon completion of this lesson, you be able to: • Define Backup and backup consideration • Describe purposes of backup • Explain backup granularity and restore • List backup methods • Describe backup/recovery process and operation

4. What is a Backup? • Backup is an additional copy of data that can be used for restore and recovery purposes • The Backup copy is used when the primary copy is lost or corrupted • This Backup copy can be created by: • Simply copying data (there can be one or more copies) • Mirroring data (the copy is always updated with whatever is written to the primary copy)

5. It’s All About Recovery • Businesses back up their data to enable its recovery in case of potential loss • Businesses also back up their data to comply with regulatory requirements • Backup purposes: • Disaster Recovery • Restores production data to an operational state after disaster • Operational • Restore data in the event of data loss or logical corruptions that may occur during routine processing • Archival • Preserve transaction records, email, and other business work products for regulatory compliance

6. Backup considerations • Primary considerations in selecting and implementing a specific backup strategy – the amount of data loss and downtime that a business can endure in term of RTO and RPO. • Retention period – duration for which a business needs to retain the backup copies. • Backup media type –based on retention period and accessibility. • Time to perform backup – to minimize any disruption to production operations.

7. Other Considerations: Data • Location • Heterogeneous platform • Many organization have dozens of heterogeneous platforms supporting complex solutions. • i.e. data warehouse environment that uses backup data from ay sources, the backup process must address these sources in terms of transactional and content integrity. • This process must be coordinated with all heterogeneous platforms on which the data resides. • Local and remote • Is the backup for local or remote site

8. continue • File size –Large-size files may use less system resource than backing up an equal amount of data comprising a large number of small-size files. • 10 files of 1MB size vs. 10000 files of 1KB size • The use of data compression can save space • Text files compresses really well • Binary files cannot compress very well • Files such as JPEG and ZIP are already compressed and therefore is unlikely to be compressed further • The number of files to be backed up also influences the backup process- need more time to search through a file system.

9. Backup Granularity –level of details backup data • Backup granularity – depends on business needs and required RTO/RPO. • Full backup • Backup of the complete data at a certain point in time • Advantages: • All files from the selected drive(i.e.) and folders are backed up to one backup set. • Easy to restore files- restore from the single backup set • Disadvantages: • More time consuming • Require more space

10. Continue… • Incremental backup • Copies data that has changed since the last full or incremental backup which ever has occurred more recently. Example : Monday – perform the first I.B of selected files and folder with the incremental option Tuesday – perform another backup with the backup file set you created on Monday. Only files that have changed since Monday’s backup are backed up. Wednesday – perform another backup with the backup file set you created Monday. Only files that have changed since Tuesday’s incremental backup are backed up. • Advantages: • Backup time is faster than full backup • IB require less disk/space • You can keep different versions of the same files on different backup sets • Disadvantages: • In order to store all the files, you must have all the incremental backups available. • Take longer time to restore a specific file since you must search more than one backup set to find the latest version of a file.

11. Continue.. • Cumulative (differential) backup • Copies data that has changed since the last full backup • Saves only the files that are different or new since the last full backup Example; Monday – perform a full backup and save the file set. Tuesday – perform a differential backup using the same file set. All files that have changed since the full backup are backed up in the differential backup. Wednesday – perform a differential backup using the same file set. All the files that have changed since Monday’s full backup are backed up. • Advantages: • D.B require very less space • Backup time is faster than full or IB • Disadvantages: • Restoring all your files may take longer time since you need to restore both the last differential and full backup

12. Continue.. • Synthetic (constructed) full backup • A full backup generated from the latest full backup and all the incremental backups performed after that full backup • Enables full backup copy to be done offline • A synthetic backup is identical to a regular full backup in terms of data, • However it is created when data is collected from a previous, older full backup and assembled with subsequent incremental backups. • The incremental backup will consist only of changed information. • A synthetic backup would be used when time or system requirements do not allow for a full complete backup. [ref: http://www.webopedia.com/TERM/S/synthetic_backup.html]

13. Continue.. Ref: Symantec.images

14. Full Backup Su Su Su Su Su Cumulative (Differential) Backup Su Su Su Su Su M T W T F S M T W T F S M T W T F S M T W T F S Incremental Backup Su Su Su Su Su M T W T F S M T W T F S M T W T F S M T W T F S Amount of data backup Backup Granularity

15. Restore operations • Restore operations vary with the granularity of the backup. • A full backup provides a single repository from which data can be easily restored. • The restoration from IB requires the last full backup and all the IB available until the point of restoration. • The restoration from a cumulative backup requires the last full backup and the most recent cumulative backup.

16. Key Features Files that have changed since the last backup are backed up Fewest amount of files to be backed up, therefore faster backup and less storage space Longer restore because last full and all subsequent incremental backups must be applied Monday Tuesday Wednesday Thursday Friday Files 1, 2, 3 File 4 Updated File 3 File 5 Files 1, 2, 3, 4, 5 Incremental Incremental Full Backup Incremental Production Restoring from Incremental Backup

17. Continue.. • A full backup is performed on Monday evening. • Each day after that IB is performed. • On Tuesday, a new file (file 4 ) is added, and no other files have changed. • Consequently only file 4 is copied during the IB performed on Tuesday. • On Wednesday no new files is added, but file 3 has been modified. Therefore only the modified file 3 is copied during the IB on Wednesday evening. • The IB on Thursday copies only file 5. • On Friday morning, data corruption – need to restore data. • Steps in data restoration: • Restore all data from the full backup on Monday evening. • Apply the IB on Tuesday, wed and Thursday • Hence data can be successfully restored to its previous state

18. Key Features More files to be backed up, therefore it takes more time to backupand uses more storage space Much faster restore because only the last full and the last cumulativebackup must be applied Friday Monday Tuesday Wednesday Thursday Files 1, 2, 3 File 4 Files 4, 5 Files 4, 5, 6 Files 1, 2, 3, 4, 5, 6 Full Backup Cumulative Cumulative Cumulative Production Restoring from Cumulative Backup

19. Continue… • A full backup is taken on Monday evening. • Each day after that, a cumulative backup is taken. • On Tuesday, file 4 added and no other data is modified since the previous full backup on Monday evening. • Hence, the CB on Tuesday evening copies only file 4. • On wed, file 5 is added. • The CB taking place on Wednesday evening copies both file 4 and 5 because both files have been added /modified since the last full backup. • On Thursday, file 6 is added- the CB on Thursday evening copies all three files, 4,5, and 6. • Friday-data corruption – need to restore • Restoration using CB: • Restore all data from full backup done in Monday • Apply only the latest cumulative backup – Thursday evening • the production volume data can easily be restored to its previous sate on Thursday evening.

20. Backup Methods • Cold or offline • The application is not active during the backup process. • Hot or online • The application is up and running when backup is performed, users accessing their data during the backup process. • Is used in a situation where it is not possible to shut down the database. • Disadvantage: affect overall application performance.

21. Continue.. • Backing up online production data is challenging because a file may be locked by the OS and cannot be copied until it is closed. There are two ways to handle this • Retry until file is closed and can be accessed • Use Open File Agents • These agents interact directly with the OS and enable the creation of consistent copies of open file.

22. continue • Point in Time (PIT) copy method is deployed in environments where the impact of downtime from a cold backup or the performance resulting from a hot backup is unacceptable. • Copies snapshots of changed data • Consumes small space and can be created very quickly

23. Continue… • In a disaster recovery environment – bare-metal recovery (BMR) – refer to backup in which all metadata, system information and application configurations are appropriate backup for a full system recovery. • BMR builds the base system – includes partitioning, the file layout, the OS, the applications and all the relevant configurations. • BMR recovers the base system first before starting the recovery of data files. • Notes: • Bare-metal restore is taking a physical machine that has crashed, and bringing it up on another physical machine.[example]-ref:http://searchdisasterrecovery.techtarget.com/podcast/What-you-need-to-know-about-bare-metal-restore-and-bare-metal-recovery

24. Backup Architecture and Process • Uses client/server architecture • Backup client • Sends backup data to backup server or storage node • Can be local to the server or they can reside on another server • Backup server • Receives backup metadata from the backup clients to perform its activities. • Manages backup operations and maintains backup catalog • Storage node • Responsible for writing data to backup device • In backup environment, a storage node is a host that controls backup devices. • Integrated with the backup server and both are hosted on the same physical platform. Metadata Catalog Storage Array BackupData Backup Data Application Server& Backup Client Backup Server& Storage Node Tape Library

25. Start of scheduled backup process 1 Backup server retrieves backup related 2 information from backup catalog Backup server instructs storage node to 3a load backup media in backup device Backup server instructs backup clients to 3b send its metadata to the backup server and data to be backed up to storage node 3b 4 Backup clients send data to storage node 4 Storage node sends data to backup device 5 1 3a 5 Storage node sends media information to backup server 6 2 Backup server update catalog and records 7 6 7 the status Backup Operation Application Server and Backup Clients Backup Server Storage Node Backup Device

26. Backup server scans backup catalog 1 to identify data to be restore and the client that will receive data Backup server instructs storage node 2 to load backup media in backup device Data is then read and send to backup 3 client Storage node sends restore metadata 4 to backup server 3 Backup server updates catalog 5 2 1 3 5 4 Restore Operation Application Server and Backup Clients Backup Server Storage Node Backup Device

27. Lesson Summary Key points covered in this lesson: • Purposes for Backup • Considerations for backup and recovery • Backup granularity • Full, Cumulative, Incremental • Backup methods • Backup/recovery process and operation

28. Lesson: Backup/Recovery Topologies & Technologies Upon completion of this lesson, you be able to: • Describe backup topologies • Direct backup • LAN and LAN free backup • Mixed backup • Detail backup in NAS environment • Describe backup technologies • Backup to tape • Backup to disk • Backup to virtual tape

29. Backup Topologies • There are 3 basic backup topologies: • Direct Attached Based Backup • LAN Based Backup • SAN Based Backup • Mixed backup

30. Data Metadata LAN Direct Attached Backups Backup Server Application Server and Backup Client and Storage Node Backup Device • Backup device is attached directly to the client • The metadata is sent to the backup server via LAN • Fees LAN from backup traffic

31. LAN LAN Based Backups Application Server and Backup Client Backup Server Metadata Data • All servers are connected to the LAN • All storage devices are directly connected to the storage node • Data to be backup is transfer from the backup client to the backup device over the LAN • This affect the network performance • Use dedicated storage nodes for some application servers. Backup Device Storage Node

32. SAN Based Backups (LAN Free) FC SAN LAN Metadata Data Backup Device Backup Server Application Server and Backup Client • Good solution when a backup device needs to be shared among the clients. • The backup device and clients are attached to the SAN. • The backup data traffic is restricted to the SAN, and backup metadata is transported over the LAN. • LAN performance not degraded since the volume of metadata is insignificant when compared to production data. • Improves backup to tape performance as LAN is free from backup traffic. Storage Node

33. Mixed Backup • Uses both the LAN-based and San based topologies. • Implemented for several reasons: • Cost, server location, reduction in administative overhead and performance considerations. Application Server and Backup Client Metadata FC SAN LAN Metadata Data Application Server and Backup Client Backup Server Backup Device Storage Node

34. Backup in NAS Environment – Server Based • Use NAS head • It use a proprietary OS and file structure supporting multiple file-sharing protocols. • In this environment, backup can be done in 4 different ways: server based, serveless, network data mgmt. protocol (NDMP)2 way and 3 ways. Storage LAN FC SAN NAS Head Application Server (Backup Client) Backup Device • NAS head retrieves data from storage over the network and transfers it to the backup client running on the app.server • The backup client sends this data to a storage node which writes the data to the backup device. Backup Request Data Metadata Backup Server/ Storage Node

35. Backup in NAS Environment – Serverless • The network share is mounted directly on the storage node. • Avoid overloading the network during the backup process and eliminates the need to use resources on the production server. • In this, the storage node(backup client) reads the data from the NAS head and writes it to the backup device without involving the app server. • This eliminates one network hop. Storage LAN FC SAN NAS Head Application Server (Backup Client) Backup Device Backup Request Data Metadata Backup Server / Storage Node

36. Backup in NAS Environment – NDMP 2-way • Backup data is sent directly from the NAS head to the backup device. • Metadata is sent to the backup server. • In this odel, network traffic is minimized by isolating data movement from the NAS head to the locally attached tape library. • Only metadata is transported on the network. Storage LAN FC SAN NAS Head Application Server (Backup Client) Backup Device Backup Request Data Metadata Backup Server

37. FC SAN LAN LAN Backing up a NAS Device – NDMP 3-way • Data is not transferred over public network. • A separate private backup network must be established between all NAS heads and the backup NAS head to prevent any data transfer on the public network. • Metadata and NDMP control still transferred across the public network. • Useful when have limited backup devices NAS Head FC SAN Storage Application Server (Backup Client) NAS Head Backup Device Backup Request Data Metadata Backup Server

38. Backup Technology options • Backup to Tape • Physical tape library • Backup to Disk • Backup to virtual tape • Virtual tape library

39. Data fromStream 1 Data fromStream 2 Data fromStream 3 Tape Backup to Tape • Traditional destination for backup • Low cost option • Sequential / Linear Access • Multiple streaming • Backup streams from multiple clients to a single backup device

40. Drives Drives Cartridges Import/ Export Mailbox Linear Robotics System Power Systems Server Class Main Controller I/O Management Unit Front View Back View Physical Tape Library

41. Tape Limitations • Reliability • Restore performance • Mount, load to ready, rewind, dismount times • Sequential Access • Cannot be accessed by multiple hosts simultaneously • Controlled environment for tape storage • Wear and tear of tape • Shipping/handling challenges • Tape management challenges

42. Backup to Disk • Ease of implementation • Fast access • More Reliable • Random Access • Multiple hosts access • Enhanced overall backup and recovery performance

43. Tape versus Disk – Restore Comparison 24Minutes DiskBackup / Restore 108Minutes TapeBackup / Restore 0 10 20 30 40 50 60 70 80 90 100 110 120 Recovery Time in Minutes* Typical Scenario: • 800 users, 75 MB mailbox • 60 GB database *Total time from point of failure to return of service to e-mail users Source: EMC Engineering and EMC IT

44. LAN FC SAN Virtual Tape Library • Virtual tape is an archival storage technology that makes it possible to save data as if it were being stored on tape even though it may actually be stored on hard disk or on another storage medium. • Benefits of virtual tape systems include better backup and recovery times and lower operating costs. [http://searchstorage.techtarget.com/definition/virtual-tape] Backup Server/ Storage Node Virtual Tape Library Appliance Emulation Engine Storage (LUNs) Backup Clients

45. Tape Versus Disk Versus Virtual Tape

46. Data De-duplication • Data de-duplication refers to removal of redundant data. In the de-duplication process, a single copy of data is maintained along with the index of the original data, so that data can be easily retrieved when required. Other than saving disk storage space and reduction in hardware costs, (storage hardware, cooling, backup media, etc), another major benefit of data de-duplication is bandwidth optimization.

47. Lesson Summary Key points covered in this lesson: • Backup topologies • Direct attached, LAN and SAN based backup • Backup in NAS environment • Backup to Tape • Backup to Disk • Backup to virtual tape • Comparison among tape, disk and virtual tape backup

48. Chapter Summary Key points covered in this chapter: • Backup and Recovery considerations and process • Backup and Recovery operations • Common Backup and Recovery topologies • Backup technologies • Tape, disk, and virtual tape

49.  Check Your Knowledge • What are three primary purposes for backup? • What are the three topologies that support backup operation? • Describe three major considerations of backup/recovery. • What are the advantages and disadvantages in tape and virtual tape backups? • What are the three levels of granularity found in Backups? • How backup is performed using virtual tape library?

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