Basic principles of backup policies
Andrea Mauro
vExpert and VCDX
http://vinfrastructure.it/en
Twitter: @Andrea_Mauro
About the speaker
 17 years of experience in IT
 Working for Assyrus Srl – Italy
● Server, Storage, Networking, Security & Virtualization
 Certifications and accreditations
 Italian VMUG founder and board member
 VMTN Community Moderator
 Blogger http://virtual-infrastructure.it/
Agenda
What is a backup policy
Design a backup plan
What defines a backup policy
What is a backup policy
Where do backups go
How will backups be performed
What is a backup policy?
Amount of data
1 principle or rule to guide decisions and achieve results
2 procedure or protocol
Backup policy
1 set of rules to achieve the required backup goals
2 several aspects: • technical
• non technical
Input of backup policies
Requirements/Constraints
Backup policies
Backup
solutions
and
products
Procedures
 Requirements
Backup/Business Continuity Plan
Risk analysis
● Recovery Point Objective
(RPO)
● Recovery Time Objective
(RTO)
 Constraints
●
●
●
●
Business needs
Budget
Max backup window
Technical aspects
 Business Continuity Plan
(BCP)
Properties & parameters & dependencies




What
Where
How, How much, How often
Several dependencies
Wks
Days Hrs
Mins
Secs
Secs
Mins
Hrs
Days
Recovery Point
Recovery Time
Protection Methods
Recovery Methods
Synthetic Backup
Real Time Replication
Tape Backups Vaults Archival
Disk Backups Staging Off-Host
Disk Restores
Instant Recovery
Bare Metal Recovery
Wks
Tape Restores
Search & Retrieve
Backup as a process
Selection
list
Analysis
+
Backup
policies
Backup
job
Backup
data
What – Define the sources of the backup
 Required protection level
 Way to handle the backup tasks
 Type of sources
Virtual
machines
Files
Applications
Systems
 Type of “transport” at source side
● Full copy
● Incremental transfer
● Size of the sources
Way to handle the backup tasks
 Agent vs. Agent-less
● Application level
● VM level
 Hot vs. Cold
● Usually agent or specific API are needed for hot-backup
 Push vs. Pull
● Also other models
Data transfer options important
Type of sources
 Files ● Windows
● Linux / Unix
 Application data – Not a simple collection of files
 Systems ● A system is not just a set of files
● It may include also files and applications backup
 Virtual Machines – It may include also system, files
and applications backup
 For details see specific lessons on Backup Academy
 Which level of consistency?
Consistency and integrity
 Different levels
 Files
● Open files dilemma
● Windows provide VSS
 Application data
● Application that are VSS-aware
● Application specific solutions
 Systems
● Problem with the system state
 Virtual Machines
● Specific hypervisor functions are recommended
 For details see specific lessons on Backup Academy
Type of “transport” at source side
 Full copy vs. incremental copy
 LAN based vs. LAN-free
Size of the sources
 Amount of data
Type of data
How data changes
Backup consistency
 How data can be transferred from the source
● Full copy vs. incremental
● Using of compression and/or de-duplication at source side
Data transfer options important
Where – Which kind of backup destination
 Disk based
● D2D
● Logical disk or network shares
 Tape based
● D2T
● Real or “Virtual” tape
 Multi-level backup
● D2D2T
● Other levels
 Cloud
D2D
 Different type of solutions
● DAS or SAN
● NAS
● Backup Appliance
− Most NAS (and sometime VTL) based
 Pros of D2D
●
●
●
●
●
Great capacity: 1,5 TB (LTO5) vs. 2-3 TB (SATA disk)
Speed: disks IOPS could scale with RAID
Bigger scalability
Replication and disaster recovery
More flexible
D2T
 Type of tape based solutions
●
●
●
●
Tape unit: DAS with SAS or SCSI cables
Autoloader: DAS or SAN
Tape library: SAN
Virtual Tape Library (VTL): an appliance (hardware or software)
that can be used as an autoloader or tape library but it works
usually with disk instead of tapes
 Pros of D2T
● Speed: throughput of 140MBps for LTO5
● Removable support with long life?
VTL
 A tape that is a disk
● Can be used as an autoloader or tape library but it works usually
with disk instead of tapes
 Implementation
● Gateway appliance
● Implemented in D2D appliances
● But could also implemented with software based products
− Virtual appliance
 Pros of VTL
●
●
●
●
Migration from D2T to D2D
Could be used to scale a D2T solution
Could export to physical tape
Backup over SAN
How – Save to sources to the destinations
 Multi-tier (hierarchy backup)
● how data are distributed using different type of destinations
 Destination “format”:
● how data are saved in which format
● with which kind of relations with previous data
(full, incremental, differential, de-duplicated, …)
 Backup frequency
● how often are performed the backup jobs
 Backup retention
● how old data are removed from the destination
● how much data must remain
Multi-tier backup strategies
 More techniques, levels or hierarchy organization
 D2DT
 Storage Snapshots as a first level
● But not a true backup!
 Offline media
 Replication as an additional level of protection
Destination “format”
 Format of the backup data depends on the backup program
 Common way to store the data
●
●
●
●
●
Full
Differential (Cumulative)
Incremental
Reverse incremental
Synthetic
 Other aspects
● Compression
● De-duplication
● Encryption
Backup frequency
 How much
● Job scheduling
 Defined by
● RPO and business requirements
 Different schedules for different format
Backup retention
 How much data must be stored?
 Depends on
● Source type and its size
● Frequency
− more backup could mean more data that could limit the retention)
● “Format” type
− by using deduplication or incremental backup and/or compression
we can reduce the amount of backup and increase the retention
● Destination type
− that could define the amount of data that could be stored)
● Required Recovery Point Objective (RPO)
 Reclaim of expired data
Retention on D2D and D2T
 D2D
● Incremental model
● Retention vs. Space
− More disks
− Compression and/or deduplication
● Reclaim mean usually delete old files
 D2T
● Full/differential/incremental models
● Retention vs. Space
− Using off-line tapes
● Reclaim with media rotation policies
Media rotation policy
 Round Robin (FIFO)
 Grandfather, Father, Son (GFS)
 Tower Of Hanoi
 More info on
● http://en.wikipedia.org/wiki/Backup_rotation_scheme
● http://www.computer-repair.com/Backup.htm
What we covered
What is a backup policy
What make a backup policy
● What
● Where
● How
Why is important
● To design a backup solution
− Consider the backup as an entire IT process
● Could be used as a documentation of the backup procedures
and jobs
● Could be part of a BCP
● High level policy can be adapted to different type of backup products
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