Backup Restore The purpose of backup is to
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.
Backup To backup or not to back up, that is the question. – Backup is not free. – No backup is risky.
Proper Backup Procedure • • Choose your application Scheduling Implementation Inventory (content and media) Verify Automate Secure
Factors • Determine which data is critical. • Determine frequency and types of backups to be used. – Full – Differential – Incremental
Factors • Determine which data is static and which is dynamic. – Some OS installations are changed infrequently; few backups required – E-commerce may require continuous backups. – Understand the changing state of your client’s data to determine an appropriate backup sched. – Organize with partitions
Factors • Determine the appropriate media storage for your backups: – CD – DVD – Tape – Disk – Solid State?
Factors • Partitioning of disk space is used to manage backups
Choose your Backup App • Mac OS X : – Time Machine • Linux/Unix : – tar (tape archive), cpio, dump • MS Windows : – MS Windows 7 includes Backup & Restore capability – Many commercial apps are available
Enterprise Level Backup Apps • Paragon Backup & Recovery includes customer support • Backup 4 All Professional • GRBack. Pro 7
Schedule • Determine the categories of data so you can schedule the backups accordingly
Schedule • Partitions are often used to manage backups • Examples: – The OS has its own partition and may require infrequent backups if changes are quarterly – User data may require nightly backups – Users must know what partitions have backup and the frequency (SLA).
Schedule Categories • Full Archival Backup – image backup implies copying the unused space. • Differential Backup – what has changed since the last backup • Incremental Backup – what has changed since the last backup of anytype
Schedule Example • Full backup twice per year • Differential first Saturday morning of each month that is not scheduled for a full backup • Incremental each Saturday morning that is not scheduled for a Full or Differential
Other Schedule Considerations • Consider completing a backup in conjunction with and before any major system changes are scheduled.
The Actual Backup • Assignment of responsibilities – Written in the SA’s job description • Acceptance of accountability – A signed form indicating that the backup was complete, verified and secured
The Actual Backup • Hardware – Choose the media type – Centralize the backup to reduce redundancy of hardware – Not everyone archives the local “C-Drive” on general purpose workstations. (SLA and user awareness)
Backup Inventory • Inventory the backup media – Tapes and other writable media use barcodes or hand-written labels • Inventory the content of the media – The backup should have a table of contents included in the backup
Backup Inventory • The media label information: – Date – System identifier – Partition name(s) – Backup category: full, differential, incremental
Verify • 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. • Restore a small subset of random files from the backup. Verify their integrity through differences or checksums.
Verify: Firedrills • When new equipment arrives, test your backup procedure on the new equipment to verify it works correctly
Backup Automation • Automation reduces human errors. • Many pre-packaged apps include automatic scheduling • Linux/Unix backup scripts can be submitted using the cron utility. Logs can be kept in /var/log, and e-mail can be sent to the admin.
Secure The Backup • Offsite storage • Encryption: to encrypt or not to encrypt, … – Will the encryption key always be available? – Statute or contract (SLA) may require encryption
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? – Some backups can be kept on site
Secure: Example Strategy Where the backup is stored will impact service response to restore requests: – Consider keeping incremental backups on site. – Differential and full backups could be stored offsite.
Data Compression • Risks – if the media is damaged, recovery may be difficult or impossible. • Lossy – some data tolerates degradation (loss of information) • No-loss – Some data should not be compressed. Know your data!
Secure Backups • Contract to store your data in a “secret” offsite location. (Secret implies a need to know basis)
Backup Considerations • Backups slow down service. This should be included in the SLA – Files should be write-locked during backup. • Avoid doing backups during peak service hours. Schedule during early AM hours on the weekend and holidays.
Restore • Common reasons for restores – Accidental file deletion – Disk failure – Loss due to malicious attack – Disaster recovery • Fire, flood, earthquake, hacker attack, sabotage, terrorist attack, etc.
Tape Backup • Large amounts of data historically favored tape media for backup: – Tapes are portable and fairly durable.
Disk Restore from Tape • Restoring from tape can interrupt service. • Restoring from tape slows the restore process by a factor of about 5 -10 times compared to a simple disk to disk copy.
Tapes • Tape historically has been 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 transport • Some tape formats are more reliable than others.
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.
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. – Tape equipment is not free. You don’t want to purchase any more hardware than is needed.
Tape • Rotate media – Incremental backup stored on site can be reused.
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.
Backup Procedure • • Choose your application Scheduling (know your data) The actual backup Inventory (content and media) Verify Automate Secure
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