Download Lecture 1: Introduction

New SA Training
Topic 12: Backups
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Introduction
Backup types
Software
Users
Machines
Policies
Finances
Introduction
 Dan Geer (a security consultant) has said
something to the effect that Backups reliably
violate security policies at a distance.
 Three Reasons for Restores
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Accidental file deletion
Disk failure
Archival
 As we discuss backups and restores, you
should keep these three in mind.
Backup Types
 Full Backup
Backs up all selected files
Differential Backup
 Backs up all files that have been changed since the last full
backup
Incremental Backup
 Backs up all files that have been changed from the most
recent backup (either a full or previous incremental)
Delta Backup
 Similar to an incremental backup, but backs up only the
actual data in the selected files that has changed, not the
files themselves.
Newer methods
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Real-time backup
Others?
Software
Files
 Open files
 Files with “holes”
 De-duplication
 Backup software
 Does it understand applications, or just
files?
 How do restores work? (can users do
their own or not)
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Users
 Users
Management (e.g., Disaster Recovery
Implementation Plan/Business Continuity
Plan)
 End-users (restores)
 Backup operators (manage the backups)
 Legislators (laws and policies)
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Machines
 Machines
Disks
 Tapes
 Tape drives
 Robots
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Newer forms of data handling
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Online backups
Peer to peer
Others?
Policies/Other Considerations
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How often do you do a full backup?
What is your backup schedule?
What is your backup window?
How long do you need to retain data?
How often can you recycle tapes (or disks)?
What are your SLAs on restores? Are SLAs on
restores of recent data higher than those on older
data?
Is your organization subject to any special
legislation on data retention?
How much data do you need to back up?
What are your storage costs?
Backup Cost Exercise
 In-class SA finance questions, assuming you
have the following tape drive:
 Quantum SDLT 320
 Can back up 115G per hour
 Can store 320G on a single cartridge
(compressed)
 List price roughly $3000
Backup Cost Exercise (cont.)
 Assume your environment is as follows:
 100 desktops, each with a 40G hard drive
 2 file servers with 1T each
 1 web server with 200G
 1 database server with 200G
 Answer the following questions:
 Assuming you back up everything, how long would it
take to do a full backup?
 Assume the CEO comes to you and says that full
backups must be taken every day. How would you go
about providing him a cost of backup hardware (using
the SDLT 320)?
 Assume that a restore takes 5 times as long as a
backup. If the CEO asks you about using the backup
tapes as a disaster recovery mechanism, how would
you assemble a time-table of restoration?
Backup Cost Exercise (cont.)
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Develop a reasonable backup schedule, and
explain why you think is it reasonable.
Express your backup architecture as a ratio
against the baseline IT budget for your company
(assume 2 SAs @ 50K each, 1 operator @ 20K,
and choose reasonable costs for the systems
outlined above).
Present an IT budget, complete with SUM pie
chart. Include price information on Veritas
NetBackup software in your budget.
The final part of your budget should be a cost
comparison of running a completely free software
shop versus a commercial software office.