Reasons for making backups

Every company makes backups. However, I have seen several occasions where backups were not working as expected.

There are three reasons for making backups:

  • In case of a technical failure or a user-error, files are accidentally deleted. These files need to be restored;
  • After a physical disaster a recovery must be performed on another site;
  • Some data must be kept available for long time: also called archiving.

I will discuss all three reasons below.

Deleted or damaged files

In case of a user-error (for instance, someone deletes an important email of a Word document), it can be necessary to restore a file. Also after a virus outbreak data recovery can be needed.

Therefore, backups of these files need to be made at a regular basis (usually daily). It is recommended to have the backups available during the day for easy recovery if a user makes a mistake, so the backups should not be stored at a far-distant site.

Remark: Storing data on synchonized disks on another site will not work in this case! When one deletes a file, or a file is contaminated with a virus, the file on the synchronized disk is also not usable anymore.

There will always be a period in time where a file can be lost and no backup is available. For instance, if someone is deleting a newly created Word document before a backup is made of it, the file is lost. There are technical solutions for this, like always keeping an online copy of all files, but these solutions are too expensive and too complex for normal situations.

Disaster recovery

In case of a catastrophe, like a fire, flooding, terrorist attacks, collapsing buildings of explosions, physical media are no longer available. Backups must be available to restore the original situation (on another site).

Therefore it is important to have backups of not only the data, but also copies of the operating systems, and of the (paper) procedures to buildup a new system. A good backup-up site is also recommended, as well as the possibility to have new hardware available as fast as possible.

Back-ups for disaster recovery need to be stored in a safe place, outside of the building, so they will not be destroyed in case of a disaster. Experience has learned that there must be a distance of at least 5km between the main site and the backup-site.

It is crucial to test the restore procedure at least every year, including building up new hardware!


Backups for archiving must be stored for the time-period specified by law and by the company's internal procedures. Obviously the backup media must be stored at a safe place, under good climate conditions (temperature, humidity, etc). Here is my article about archiving.

Backup and business demands

There is no reason to backup data that cannot be restored. I have seen several cases of this in practice.

One example was a UNIX server with a very complicated file structure. The server could be back-upped, but restoring all data to a new machine would takes weeks to complete. This was obviously unacceptable for the business, so they stopped backing-up the data on tapes and created another solution for safeguarding data.

A second example was a Public-sector company that was part of a supply-chain. The company could restore it's data, but this was only feasible if all other companies in the supply-chain also would restore their data. This would take the whole chain a few days back in time, which was of course unacceptable.

A very interesting article about backups is "The TAO of Back-up". Click on the arrows for the complete story.

This entry was posted on Thursday 30 August 2007

Earlier articles

The cloud is as insecure as its configuration

Infrastructure as code

My Book

DevOps for infrastructure

Infrastructure as a Service (IaaS)

(Hyper) Converged Infrastructure

Object storage

Software Defined Networking (SDN) and Network Function Virtualization (NFV)

Software Defined Storage (SDS)

What's the point of using Docker containers?

Identity and Access Management

Using user profiles to determine infrastructure load

Public wireless networks

Supercomputer architecture

Desktop virtualization

Stakeholder management

x86 platform architecture

Midrange systems architecture

Mainframe Architecture

Software Defined Data Center - SDDC

The Virtualization Model

What are concurrent users?

Performance and availability monitoring in levels

UX/UI has no business rules

Technical debt: a time related issue

Solution shaping workshops

Architecture life cycle

Project managers and architects

Using ArchiMate for describing infrastructures

Kruchten’s 4+1 views for solution architecture

The SEI stack of solution architecture frameworks

TOGAF and infrastructure architecture

The Zachman framework

An introduction to architecture frameworks

How to handle a Distributed Denial of Service (DDoS) attack

Architecture Principles

Views and viewpoints explained

Stakeholders and their concerns

Skills of a solution architect architect

Solution architects versus enterprise architects

Definition of IT Architecture

What is Big Data?

How to make your IT "Greener"

What is Cloud computing and IaaS?

Purchasing of IT infrastructure technologies and services

IDS/IPS systems

IP Protocol (IPv4) classes and subnets

Infrastructure Architecture - Course materials

Introduction to Bring Your Own Device (BYOD)

IT Infrastructure Architecture model

Fire prevention in the datacenter

Where to build your datacenter

Availability - Fall-back, hot site, warm site

Reliabilty of infrastructure components

Human factors in availability of systems

Business Continuity Management (BCM) and Disaster Recovery Plan (DRP)

Performance - Design for use

Performance concepts - Load balancing

Performance concepts - Scaling

Performance concept - Caching

Perceived performance

Ethical hacking

The first computers

Open group ITAC /Open CA Certification

Sjaak Laan

Recommended links

Ruth Malan
Gaudi site
Esther Barthel's site on virtualization
Eltjo Poort's site on architecture


XML: RSS Feed 
XML: Atom Feed 


The postings on this site are my opinions and do not necessarily represent CGI’s strategies, views or opinions.


Copyright Sjaak Laan