Backup Methodologies

8/22/2019 Backup Methodologies

1/9

1

BACKUP METHODOLOGIES

Introduction

In any business scenario data plays a vital role. There is no continuity ofbusiness without availability of data. Backup is one of the data storage methods

that prepare you for the worst. Particularly utilities and critical service providerslike telecom carriers must be prepared for any kind of disaster. About 30% of

companies lack disaster recovery strategy. The lack of sound disaster recoverystrategy leaves those companies vulnerable to potential data loss as a result of

massive power outages, catastrophic disaster, viruses and the like. Faced with

such grim reality the data storage industry has responded by developingtechniques and technologies that can help you create a sound and effective

disaster recovery plan.

Rapid growth in storage bought on by Internet and distributed computingtechnologies have placed nearly impossible demands on administrators

responsible for protecting data assets. In the past several years, the

architectures of data protection have continuously changed depending onstorage milieu, enterprise backup, recovery requirements, availability of more

sophisticated software and hardware infrastructure components.

A data backup plan encompasses issues such as backup policy, frequency ofbackup, what to backup, how long to restore backed-up data and includes

onsite and offsite storage strategy. Different backup methodologies exist today

to choose from that suit the enterprise.

Backup Architectures

Depending on the data size, requirements of the enterprise, backup window,setup and location of backup there are numerous backup architectures available

today. Decentralized storage led to large-scale deployment of network backup

solutions, while recentralization of storage caused the backup models to changetowards local backup of large servers with centralized control. Lately, network-

attached storage appliances have resulted in new backup methodologies suchas NDMP (network data management protocol). More recently, increased

popularity of SAN environments has led to even newer backup architectures.

Local System Backup

Local backup is the most common and straightforward mechanism for providingprotection of data. This method installs all components like engine, data source,data mover, and everything else on the server. Using this technique involves

copying data objects like files, volumes, and databases from primary disk tosecondary storage, most commonly tape media. The main reason for running

local backup is to get faster performance from a locally attached tape drive; it

is completely self-contained, and thus not vulnerable to the availability ofnetworks or other servers. The main problem with this type of single-server

backup is the amount of management support needed. Local backup needs at


2/9

2

least one tape driver per server, one backup software per server, and multiple

tapes for each server. This is considerably more to manage than a single largenetwork backup system. The two major disadvantages are that it requires a

dedicated secondary storage device for every server and that all I/O impactsthe local server.

Fig 9. Local System Backup

Source: http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=local+backup+in+storage&btnG=Google+Search

Network (LAN/WAN) Backup

A local and wide area network backup architecture is an obvious alternative to

local backup architecture. The backup client produces a backup image from diskand sends the image across a network to the backup server, which directs this

image to secondary storage. The main advantage of using this architecture is

sharing secondary storage devices and centralized administration. Anotherimportant benefit is that using this architecture offsite backup is feasible which

is much more safer than local backup. The chief drawback of network backup isconsumption of network resources.


3/9

3

Fig 10. Network BackupSource: http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-

8&q=nas+in+storage&btnG=Google+Search

NDMP backup

Network Data Management Protocol will create first opportunity to provide trulyenterprise wide heterogeneous storage management solutions. NDMP, as an

embedded protocol, separates the data path and the control path, so networkdata can be backed up locally yet managed from a central location. NDMP

provides a means to perform backup of servers and appliances that aretypically unable to host native backup clients. Prior to NDMP, theseenvironments used remote file sharing protocols such as NFS and CIFS. In the

NDMP architecture, the host initiating and controlling the backup operation overTCP/IP is labeled as the NDMP client, and the systems performing data

movement from disk to secondary storage are labeled NDMP servers. The mainadvantage of using NDMP backups are centralized administration and the

reduction of network traffic.
http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=nas+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=nas+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=nas+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=nas+in+storage&btnG=Google+Search


4/9

4

Fig 11. NDMP Backup

Source: http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=NDMP+backup+in+storage&btnG=Google+Search

There are different backup methods existing now.Some of them are:

1. Backup to disk- it is expensive to backup to a disk. Cost per Gigabyte of diskdrives is far higher than cost per Gigabyte of tapes. However it seems thatmore and more companies are going for this backup to increase the speed ofimportant backups and dramatically decrease the restore time. A common

application of taking backup on disk drives is having a direct copy of the dataon disk. In case of data loss you can synchronize the production disk with the

backup disk made. It will still be necessary to stream this data to tapes for

long time storage.
http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=NDMP+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=NDMP+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=NDMP+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=NDMP+backup+in+storage&btnG=Google+Search


5/9

5

Fig 1. Backup To Disks

Source: http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Search

2. Removable media:a) CDR (CD recordable),b) MO (Magneto Optical) drivesc) ZIP drives, etcThis option is merely useful for relatively small amounts of data. For large

amount of data multiple volumes are to be used which makes it complex

to manage. Also it is too time consuming to backup big chunks of dataonto a backup medium with a storage capacity of less than a GB. But still

these come handy when data has to be kept for long period like archivesof tax data for instance. Two years ago one could write 650 MB to an MO

disk whereas today you can write 9 GB to that MO disk. This makes itperfect solution for backing up the desktop computers.
http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Search


6/9

6

Fig 2. CDR Fig 3. ZIP driver Fig 4.MO driver

Source: http://images.google.com/images?q=ZIP+drives+in+storage&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Search

Source:http://images.google.com/images?q=MO+drives+in+storage&btnG=Google+Search&hl=en&lr=&ie=UTF-8&oe=UTF-8

3.

Local tape drives- A widely spread method of backing up data is that everyserver has its own tape drive(s). The advantage is that one need not have to

worry about network bandwidth or the availability of a backup server. Forincreasing the capacity when tape drive is full can be done manually or extra

hardware can be used like an extra drive or a tape stacker.

Fig 5. Local tape driveSource: http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-

8&q=local+tape+drives+in+storage&btnG=Google+Search

4. Shared tape drives (one or more backup servers)- Another common methodis using a backup server. This machine has the task of gathering data of other

machines spread over a network. This can be dedicated machine or anymachine that is idle at the time of backup. For instance, if one has 50

machines to backup and do not have money to invest in a big dedicated

backup server. In this case he/she my keep 5 machines for the task of

backup each is backing up data of 10 machines. Backing up several machineswithout making careful inventory may cause the media to run out of capacity.There are future considerations like how fast are these machines to write all

data to tape in the designated backup window and are there any future plansfor these machines, what kind of support contract do each machine has on

them etc.
http://images.google.com/images?q=ZIP+drives+in+storage&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Searchhttp://images.google.com/images?q=ZIP+drives+in+storage&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Searchhttp://images.google.com/images?q=MO+drives+in+storage&btnG=Google+Search&hl=en&lr=&ie=UTF-8&oe=UTF-8http://images.google.com/images?q=MO+drives+in+storage&btnG=Google+Search&hl=en&lr=&ie=UTF-8&oe=UTF-8http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=local+tape+drives+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=local+tape+drives+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=local+tape+drives+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=local+tape+drives+in+storage&btnG=Google+Searchhttp://images.google.com/images?q=MO+drives+in+storage&btnG=Google+Search&hl=en&lr=&ie=UTF-8&oe=UTF-8http://images.google.com/images?q=MO+drives+in+storage&btnG=Google+Search&hl=en&lr=&ie=UTF-8&oe=UTF-8http://images.google.com/images?q=ZIP+drives+in+storage&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Searchhttp://images.google.com/images?q=ZIP+drives+in+storage&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Search


7/9

7

Fig 6. Shared tape drives

Source: http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=shared+tape+drives+in+storage&btnG=Google+Search

5. Tape stackers- a tape stacker is an intelligent choice when one runs out ofsingle drives capacity. A stacker works according to the sequential system.

The first tape is written until it is completely full after that second tape has itsturn, this routine repeats itself until the last tape is used up. Using a simple

schedule, this will force you to change tapes as soon as the stacker is full.
http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=shared+tape+drives+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=shared+tape+drives+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=shared+tape+drives+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=shared+tape+drives+in+storage&btnG=Google+Search


8/9

8

Fig 7. Tape Stackers

Source - http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Search

6.

Robotic tape libraries- Tape libraries refer to any tape automation productsthat are physically larger and hold more tapes than a tape stacker. Common

library configurations have two to four tape drives and can hold 20 to 400tapes. It uses a totally different mechanism than the tape stacker. The tape

library is inventory aware. This means that the library knows about howtapes are in the library. It often uses barcodes attached to the tapes as a

reference.

Libraries can use barcode readers to identify tapes as they are inserted. The

software that controls the library keeps track of the content of the tapes. Thisoffers to mix different sets of clients, schedules and retention periods.
http://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Searchhttp://images.google.com/images?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=disk+backup+in+storage&btnG=Google+Search


9/9

9

Fig 8. Robotic tape library

CONCLUSIONS:

These are some of the backup methods and architectures, which can be used

for enterprise backup. The whole aim of backup is to keep data more safer

using a simpler, cheaper and effective method.

Re f e r e n c e s :

1. Building Storage Networks - 2nd Edition by Marc Farley(StorageNetworking Industry Association)

2. Exploring Backup Alternatives In A SAN Environment http://data.fibrechannel-

europe.com/technology/whitepapers/wp_190601_1.html
http://data.fibrechannel-europe.com/technology/whitepapers/wp_190601_1.htmlhttp://data.fibrechannel-europe.com/technology/whitepapers/wp_190601_1.htmlhttp://data.fibrechannel-europe.com/technology/whitepapers/wp_190601_1.htmlhttp://data.fibrechannel-europe.com/technology/whitepapers/wp_190601_1.html

Documents

Backup Methodologies