Backup & Restore

1. Backup & Restore • The purpose of backup is to protect data from loss. • The purpose of restore is to recover data that is temporarily unavailable due to some unexpected event.

2. Backup To backup or not to back up, that is the question. • Backup is not free. • No backup is risky.

3. Factors of a Proper Backup • Planning • Scheduling • Backup operation • Inventory (content and media) • Verification • Automation • Security

4. Planning • Choose your backup app. • Determine which data is critical. • Determine frequency and types of backups to be used. • Archival (mirror or image) • Differential • Incremental

5. Planning • Determine which data is static and which is dynamic. • The OS and apps tend to be static; few backups required • E-commerce transactions may require continuous backups. • Understand the changing state of your client’s data to determine an appropriate backup sched. • Organize with partitions

6. Planning • Determine the appropriate media storage for your backups: • CD • DVD • Tape • Disk • Solid State?

7. Schedule • Full Archival Backup • Mirror backup • image backup • Differential Backup • Incremental Backup

8. Full Archival Backup • Formatted into a single file and stored on your media choice. • Mirror– every last bit on the disk is duplicated including empty space. • Image - empty space is ignored

9. Full Archival Backup (Pros) Pros • Provides a complete copy of data • Easy to manage: • Done less frequently than other types of backups : Monthly, Quarterly, semi-annually, annually.

10. Full Archival Backup (Cons) Cons • Usually requires more media space than either differential or incremental. • Takes a long time to recover the full backup to a new disk.

11. Full Archival Backup • Consider making multiple backup copies • Full backup media should be stored offsite to protect data from: • Fire • Natural disasters (flood, earthquake, etc) • Terrorist attack • Sabotage • Hacker attacks

12. Archival Addendum • Files that are not backed up cannot be subpoenaed.

13. Differential Backup • Copy the files changed since the last full backup. • Differential backups grow with time. They can eventually grow larger than the last full backup. • Scheduled less frequently than a full backups: Weekly, monthly.

14. Differential Backup (Pros) • Redundancy • Usually takes up less time and space than a full backup. • If the differential backup grows to the size of the last full backup, then schedule a new full backup.

15. Differential Backup (Cons) • Redundancy – potentially many unneeded copies of the same data (also a potential pro) • Subsequent differentials take longer and use more media space.

16. Incremental Backups • A backup of what has changed since the last previous backup of any type. • Frequency of incremental backups depends on the client needs. • Weekly, daily, hourly, continuously.

17. Incremental Backups • Pros • Keeps a revision history of actively changing files • Fastest backup type • Uses the least amount of media • Cons • Much more difficult to manage

18. Backup Inventory • Inventory the backup media • Tapes and other writable media use barcodes and labels • Inventory the content of the media • The backup may require a table of contents

19. Verify: Firedrills • The only time you know the quality of your backup media is when you are doing a restore. • This is the worse time to discover you have problems. • Pick random files from a backup and restore them.

20. Verify: • Use new hardware (servers & disks) to test the viability of your backups before putting the hardware in service

21. Firedrills • An occasional test of a full partition restore is not unreasonable. This would be done if • A change is made in the backup software release. • A change of vendor for the backup software product. • When a new server with new unused disk arrives.

22. Backup Automation • Non automated backups are dangerous. • Automation reduces human errors. • Choose your app for backup • Carbon Copy Cloner • Macrium Reflect • Tar, cpio, dump, dd

23. Secure: Off-Site Storage Off site storage has risks all its own • Data can be lost/destroyed in transit • How important is it to have a backup of the backup?

24. Data Compression • Risks – if the media is damaged, recovery may be difficult or impossible. • Lossy compression is not suitable for many kinds of data. OK for images, video, or sound. Know your data! • No-loss compression for data base files, applications, etc.

25. Backup Compression & Encryption Pros • Compression saves space • Encryption provides security Cons • Lost encryption keys make recovery impossible • Some damaged media can be partially recovered. Consider a Mirror Archive (no compression or encryption)

26. Backup Addendum • Backups slow down service. • Files are write-locked during backup. • Backups should not be done during peak service hours. Schedule during early AM hours on the weekend.

27. Restore • Three reasons for restores • Accidental file deletion • Disk failure • Disaster recovery • Fire, flood, earthquake, hacker attack, sabotage, terrorist attack, etc.

28. Accidental File Deletion • If backups are once per day, lost work is limited to one day for a given file. (RAID does not help) • As storage technology gets cheaper by the Gbyte, it becomes easier to implement more sophisticated storage procedures that are more timely. (Mirror backup). • A user wants the restoration to be immediate. The quicker the turnaround, the happier your customer.

29. Tapes • Tape is (or was?) the preferred backup media for very large data storage environments. • Tape has a useful life span. • Tape can be very robust for storage • Easy to tansport • Some tape formats are more reliable than others.

30. Tape Inventory • Backup tapes must be • Properly labeled • Properly stored • Proper inventory is needed to do restores in a timely fashion. • Hand written labels are ok • Bar codes and printed labels are better.

31. Tape Inventory • Inventory is not limited to the physical tape itself. • The contents of tapes must be inventoried. • The number of accesses must be logged because tapes ware-out.

32. Tape Standards • 8mm • DLT • DAT (4mm) • QIC • http://www.pctechguide.com/15tape.htm • Imation.com

33. Tape Technology • Tape technology expands in leaps. • Tape hardware purchases are not made on a constant basis (like disk storage). • Tape technology is purchased in leaps. Three year intervals are more practical.

34. Centralization • Costs can be reduced through centralization • Tape mounts are labor intensive, so look to automation. Con • No need for hardware or manpower duplication • Equipment can be interchanged more easily when centralized.

35. Technology • Disk space cost drops by 1/2 about every 18-24 months. • Disk space is filled as it expands. • Disk requirements are increasing on a continuous basis. • Disk budgets increase faster than tape backup budgets.