Backup Tips And Strategies For Artists

A backup, in computer lingo, refers to making a copy of

important data for the purpose of data recovery. Should

the important data get damaged or lost, a properly made

backup will restore it all. The word "data" refers to

anything stored on a computer system: images, programs,

document, videos, etc. Taking backups of important data

can prevent loss of valuable work and the time needed

to recreate it.

In this article we'll take a look at common backup types

and strategies, data compression, and common backup media

types. A real life backup scenario will illustrate my

own backup procedures. The article will end with general

backup tips.

COMMON BACKUP TYPES

The best backup methods rely on simple and time proven

concepts. New or unnecessary technologies are best

avoided till proven reliable and necessary. The simpler

the procedure, the more likely it is to work correctly.

A full-backup consist of making a copy of all important

data. When you copy a folder with important files,

from say a hard drive to a floppy, you actually make

a full-backup of those files. Due to simplicity,

this approach is the most reliable of all backup

types. Its main advantage is ease of backup creation

and restoration. The main disadvantage is that the

backup will use as much space as the important data. If

the data is large, the backup process can be very

resource intensive in terms of time and the processing

power needed to carry out. Imagine the time needed to

full-backup a digital library consisting of millions of

books. Such operation takes days.

An incremental-backup works differently in that it backs

up only the modified files since the last backup. When

using this method, a full backup is created first and

then incremental backups are run on regular basis. For

large amounts of data this method is often the only

practical way to backup. It takes up less space than a

full backup and is less resource intensive to run. On

the other hand, contrary to full backups, incremental

backups need dedicated backup software to keep track of

what files to backup.

Compressing the backup data is a popular option. Such

practice lowers the amount of space needed on the backup

media. Although compression adds an additional layer

of complexity, it can be a good (if relied on wisely)

and sometimes necessary solution.

ESSENTIAL BACKUP STRATEGIES

Regardless of the backup type and data, the following

backup strategies should always be followed:

backup should be taken on a regular basis
backup should be automatic and need as little human supervision as possible
backup should be stored in a safe remote location
backup should rely on well established hardware and software technologies

Backup should be taken on a regular basis. The more

frequently the data changes the more often it should

be backed-up. For example, some of my most frequently

updated files (website files, source code, notes,

etc.) are backed-up daily. Files that are less

frequently updated are backed-up monthly.

Backup should be automatic. Except for the initial

configuration of the backup program and the occasional

supervision, the whole backup process should be automatic

and completely transparent. That is, the backup should

run by itself without causing any attention unless

necessary.

Backup should be stored in a safe remote location. Should

the location of the important data get damaged,

destroyed, or exposed to theft - a remotely stored backup

becomes invaluable. How remote? Disasters like fire,

flood, tornado, earthquake, etc., can cause widespread

damage. Ideally a backup should be stored in a far away

enough, minimal risk location.

Backup should rely on well established hardware and

software technologies. Such technologies are typically in

widespread use - thus cheaper and easier to troubleshoot,

or get help in the event of failure. As established

technologies become gradually replaced by new and

better ones, so should the backup media and hardware

and, if used, the software to re/store the data. There

is no guarantee that the common backup media of today,

like CD or DVD, will be usable in ten years. The same

is true for software. A good data preservation strategy

should include continual migration of the backup data

to mature and well established technologies of the time.

A BIT ABOUT DATA COMPRESSION

Compression makes data smaller and thus is a popular

backup option. Its main advantage is lower backup

cost due to lower space use. The downside is the time

needed to compress the data and later to uncompress it

for restoration.

Many compression formats exist. Each format use some

sort of compression method called an algorithm. There

are two types of data compression algorithms: "lossy"

and "lossless". Lossless compression reduce the data

size without modifying its content. Lossy compression

modify the data content to make it even smaller than

lossless compression.

Some compression formats, like MP3 or JPG, are highly

specialized. They use lossy algorithms and produce very

small file sizes but can only compress a particular

type of data. Other formats, like ZIP or BZIP2, are

of general purpose. They rely on lossless compression

algorithms and can work on any data. However, they will

never outdo special purpose formats like MP3 or JPG.

PNG and TIFF are popular image file formats which support

lossless compression.

Unfortunately, due to the nature of lossy compression,

JPG, MP3 or any other lossy format degrade the original

data to some extent. In other words, saving an image or

music in a lossy file format will make it different then

the original. Usually the difference, called compression

artifacts, is so small that most of us don't see or

hear it.

For the above reasons, lossy compression should never

be used when saving important data. Only lossless

compression is suitable for that. PNG and TIFF are

examples of image file formats that support lossless

compression. Such formats are ideal for storing

hi-resolution master images.

Finally, compression takes time and normally uses all

available processing power. Generally, the better the

compression the slower it is. Some compression algorithms

are extremely good at compressing but also extremely

slow. For backup purposes, one should evaluate common

compression formats and set for the most suitable one.

CONSIDER YOUR NEEDS

Some additional issues need to be considered when

designing the most suitable backup strategy for own use:

the type of backup files
if compression is desired, what compression to use and how
backup storage media

As noted earlier the best backups are simply copies of

important data. Such approach works especially well for

artists who rely on compressed image formats like PNG

or TIFF.

Note the difference between "built-in" image compression,

done every time you save an image in a format that

supports it, and compressing the backup data - applied

to all backup data regardless of what it is.

What backup compression to use, and if to use it at all,

depends on the type of backup data. Generally,

text files (TXT, HTML, XML, etc) can be compressed

the most of all file types. Images that have been

compressed with their own algorithms (PNG, JPG, TIFF,

etc) can't later be compressed much if at all. Images

which don't have own compression (BMP, TGA, etc) can

often be compressed quite a bit, though this depends on

the actual image data.

Thus if most of your important art data consist of

images that are already compressed, there is no need to

compress the backup. Text files on the other hand, can

be compressed a lot and save significant amount of space.

There are a few other things to consider when compressing

backup data. What compression program to use and how

to compress the files.

ZIP is the most commonly used compression format today -

it's fast and compresses well. It's been around for a

long time and is universally available. But there are

other, less known, good alternatives. For example,

7ZIP, RAR, and BZIP2 compress significantly better than

ZIP and are only slightly slower.

Finally, how to compress backups. Basically one can

either create a compressed archive of many files, or

compress each file individually. The main disadvantage

to creating a compressed archive is the possibility

of losing all files in the archive if the archive

gets corrupted and can not be recovered. On the

other hand, if files are compressed individually one

looses only one file - should it get corrupted and be

unrecoverable. Additionally, since a compressed file

use less space than uncompressed, it's less likely to

get corrupted. Thus it's more safe to compress files

individually.

WHICH BACKUP MEDIA TO USE

The commonly used backup media today are hard drives,

tapes and CDs/DVDs. Hard drives are the fastest and

often the best option for large amounts of data. They are

also the most expensive and not very durable. Tapes are

slow but can store a lot of data and can last decades.

CDs/DVDs are probably the most common backup media used

today due to its very low cost. Unfortunately, just

like hard drives, most have a relatively short expected

life span of between two to five years. Internet backup

solutions are also becoming a popular backup option.

Reliability is important to consider when choosing the

backup media. How robust is the media and for how long

can it retain the data? The quality of the media plays

a significant role here. All media degrade over time,

but some degrade more than other. Most of the low cost

burnable CDs have a life span of around two years. Higher

quality CDs can last up to five. Very high quality

CDs with a gold layer are expected to last decades.

Generally, if the handling and storage conditions

are good, quality media should last at least few years

without data loss. However, unless the best quality media

is used, an annual full backup is probably the safest

prevention against data loss due to media degradation.

A combination of different media may often be the ideal

solution. For example, some of my own backup practices

include using an external hard drive to mirror (update)

certain parts of my computer hard drives. Twice a year

I burn all important data on several DVDs.

I recommend spending some time investigating the most

suitable media and the hardware to operate it. High

quality products will minimize the possibility of

backup failure.

THE NECESSITY OF VERIFYING BACKUPS

The most important aspect of taking backups is making

sure they are error free. The backup data may prove

useless if corrupted due to media or other error.

It's good practice to immediately test the backup for

its validity. Errors will be detected and a new backup

can be taken right away. Any respectable backup program

provides an option for data verification. What good is

a backup if its data is corrupted?

A REAL LIFE BACKUP SCENARIO

My most valuable data is my art data, website files,

source code, and various docs. All my hi-resolution work

is stored in either PNG or TIFF. Nearly all my reference

images are JPGs. Thus all my image data can be backed

up without the use of compression and save huge amounts

of backup time and space. I do compress 3d files which

don't use own compression. For that I use bzip2 with the

maximum compression setting. All the remaining data are

basically text files and are compressed individually

using either bzip2 or 7zip. Images and 3d files, even

compressed, can be huge in size. Not surprisingly over

90% of my backup space is used on art data.

I backup daily, monthly and twice a year. Once a day,

the files which are frequently updated (notes, work

in progress images, source code, website files, email,

etc.) are backed up to another hard drive. This happens

during the boot process and takes a few minutes. Once

a month I backup to a CD which also includes less

frequently updated files. A copy of that CD is stored

in a remote location. Twice a year I take full backup

and store it on several DVDs at a friends house. If I

work on something especially important, I store it daily

on a CD/DVD or a USB mem-stick. My most critical data

is also regularly encrypted and stored on a very remote

internet host. I wrote a script to run all these backups

automatically. With the exception of CD/DVD storage,

no manual work is involved.

As you can see, a custom backup solution can be quite

sophisticated yet simple to carry out. It can involve

a combination of different media and backup procedures

to optimally satisfy ones needs.

FINAL NOTES

Depending on your needs a dedicated backup software may

be a necessary investment. Make sure to research this

carefully. Usually, products from reputable companies

that specialize in certain solutions are best. There are

also many good open source or free software alternatives.

It's best to avoid products which rely on proprietary

or closed solutions. For example, a backup software

may store the backup data in an unknown format only

supported by this particular backup software. Avoid

that. If the company goes out of business and the

backup software breaks, your backup data may be lost

forever. Look for products that rely on well known,

mature, and ideally open technologies. For example,

PNG is an open format for storing image data. What this

means is that the specification, or blueprint, for that

format is publicly available for anyone to use it. This

increases compatibility and reduces reliance on any

specific vendor or product.

Most artists important data consists mainly of images

and 3d files. To save space rely on PNG, TIFF or JPG

for bitmap image formats. Vector images and 3d files

can be compressed individually if needed. A basic

backup software that simply copies specified files

or directories to the backup media may be all that

is needed. It's best to make two sets of the backup

data and store each at different location. One close

to home, like a friends place, or a bank box and the

other far away.

Setting up a proper backup strategy may initially require

a significant amount of time and cost money. There is

a lot to research and consider. In the end however,

a good backup procedure will prove an exceptionally

valuable investment. As you read this, your screen could

go blank due to a hard drive crash. All your valuable

data - years of work, reference images, documents,

photo albums, 3d files, email, etc., - could be lost

forever. Unless you were prepared and took a backup.

Dawid Michalczyk is a freelance illustrator and an artist. He has been creating computer graphics since the early 90s. To see examples of his work and other writings visit his website at http://www.art.eonworks.com. He can be reached at dm@eonworks.com

Tape Backup Strategies

Before you can have a secure and effective plan for managing your data, you must incorporate a strategy that includes the following information:

• The importance of the data you are backing up

• How often to back up your system

• How many tapes you will use

• When you will use certain tapes

• How you will keep track of your backup information

Choosing a Backup Strategy.

Several tape rotation schemes are described in this chapter. Prior to choosing a strategy to use with your Backup Exec system, you should examine the following questions.

How often should I back up?

While there is no set rule on how often to back up your data, there is one consideration that can help you decide for yourself: What is the cost of recreating data that was added or modified since the last backup?

Calculate the manpower, lost time and/or sales and other costs that would be incurred if your system crashed just before the next backup was to take place (always assume the worst-case scenario). If the cost is excessive, the strategy needs to be adjusted accordingly.

For example, if you have a database containing important customer information that you update several times a day, the cost to recreate that information would probably be quite substantial. On the other hand, the cost to recreate the data for one or two inter-office memos would be considerably less.

Ideally, you would want to do at least one Normal backup of all drives, directories, and files every day. Important files and directories that constantly change may need to be backed up several times a day. For safety reasons, a Normal backup should always be performed before adding new applications or changing your system's configuration.

How long does the data need to be stored?

The amount of time the data needs to be stored is directly related to the tape rotation scheme you use. For example, if you use one tape and back up every day, your backups will never be more than a day old.

Since tape media is relatively inexpensive when compared to the value of your data, it is a good idea to periodically backup your system on a tape not used in the tape rotation scheme and store it permanently.

The threat of viruses is an issue here also. Some viruses take effect immediately, while others may take days or weeks to cause noticeable damage. Because of this, you should have at least the following backups available to restore at any time:

• 3 daily backups (i.e., Monday, Tuesday, Wednesday)

• A one-week-old Normal backup

• A one-month-old Normal backup

Having these backups available should allow you to restore your system prior to when it became infected.

Important: Be careful not to restore data you think may be infected to a drive that is not infected.

What is the life expectancy of a tape?

Tapes that are used over and over will eventually become old and worn out. When this happens, the success of restoring data from those tapes diminishes. Since tape media is relatively inexpensive, it is a good idea to periodically replace your older tapes with new tapes.

Set a standard as to how long you can use a tape before you replace it based on the backup strategy you use, the number of times you use the tape, and how long you plan to keep the tape. Also, if the quality and reliability of a tape becomes questionable (you begin to get tape errors during a backup operation), you should replace the tape.

The suggested standard to be:

• if the tape is used once a week then dispose of after 3 months

• if the tape is used often then dispose of after 6 months

• if the tape is used periodically then dispose of after 12 months.

Backup Methods

There are five backup methods:

Method - Description

Normal - Normal backups will back up all selected drives, directories, and files regardless of whether or not they have changed since the last backup (resets the archive bit).

Incremental - Incremental backups will back up only the files that have been created or changed since the last Normal or Incremental backup (resets the archive bit).

Differential - Differential backups will back up all files that have been created or changed since the last Normal backup (does not reset the archive bit).

Copy - Copy backups will back up all selected drives, directories, and files and does not affect subsequent Incremental or Differential backups.

Daily - The Daily Backup method backs up all files with today's date (created or changed today) and does not affect the files' backup status (does not reset the archive bit).

Before you can develop your tape rotation scheme, you will need to decide whether you want to do Normal, Incremental, Differential, or Daily backups or a combination. There are advantages and disadvantages to each method. Copy and Daily backups may be performed in addition to the tape rotation scheme selected.

Normal Backups

Advantages

Files are easy to find - Since Normal backups include all data contained on your hard drive, you do not have to search through several tapes to find a file that you need to restore.

There is always a current backup of your entire system on one tape or tape set - If you should need to restore your entire system, all of the most current information is located on the last backup.

Disadvantages

Redundant backups - since most of the files on your system rarely change, each backup following the first is just a copy of what has already been backed up.

Normal backups take longer to perform - Depending on how much data you are backing up, Normal backups can be time consuming.

Incremental Backups

Advantages

Better use of media - Only files that were created or changed since the last backup are included, so there is much less data storage space required.

Less time required for backup - Incremental backups take much less time than Normal backups to complete.

Disadvantages

Files are more difficult to find - Incremental files may be spread across all tapes used since the last Normal backup. You may be required to search several tapes to find the file you want to restore (this is typically not a problem if you use full cataloging and Backup Exec's Advanced File Selection feature).

Full restoration of your hard drive may be time consuming - Restoring a hard drive will probably require the restoration of data from more than one tape. This can take more time than if all data was on a single tape.

Differential Backups

Differential backups include backing up all files that were created or changed since the last Normal backup. For example, let's say you perform a Differential backup on Monday following Friday's Normal backup. When you perform a Differential backup again on Tuesday, the backup will include the data you backed up Monday, as well as any files that were changed on Tuesday. If you had performed an Incremental backup on Monday and Tuesday, Tuesday's backup would include only files that were created or changed since Monday's backup.

Advantages

Files are easy to find - Restoring a system backed up under the Differential backup strategy requires a maximum of two tapes-the latest Normal backup tape and the latest Differential backup tape. This potentially represents a considerable time savings over backup strategies which require the latest Normal backup tape and all Incremental backup tapes created since the Normal backup.

Less time required for backup - Differential backups take much less time to complete than Normal backups.

Disadvantages

Redundant backups - The amount of data backed up each day following a Normal backup gets greater and greater. For example, let's say you are performing a Normal backup on Friday, and Differential backups Monday through Thursday. Redundancy occurs because the same information backed up on Monday will be backed up again three times (Tuesday, Wednesday, and Thursday).

Copy Backups

Copy backups may be performed in addition to the tape rotation scheme selected. Copy backups allow you to perform a backup to meet a specific purpose (e.g., create a special tape, backup specific data, etc.).

Daily Backups

Daily backups may be performed in addition to the tape rotation scheme selected. The Daily Backup method backs up all files with today's date (created or changed today). The Daily Backup method does not affect the files' backup status (does not reset the archive bit).

Tape Rotation Schemes

There are many different tape rotation schemes. They differ mostly by the number of tapes they require and how long the tapes are kept before they are rotated back into the schedule. The tape rotation schemes described here are:

• Son

• Father/Son

• Grandfather

• Ten Tape

Stick to the Schedule

To realize the maximum benefits of your tape rotation scheme, stick to the schedule. If the schedule is not followed regularly, mistakes could take place that would render all backup efforts useless. Make sure that backups of your system are performed on schedule.

The tape rotation schemes described here are generic. Depending on the value and quantity of your data, you may want to adjust a schedule to better fit your needs. For example, if you are using the Grandfather scheme, you may want to perform a Copy backup on the last Saturday of the month to rotate off-site for permanent storage.

Son Scheme

Number of tapes required: 1

Maximum Storage life: last backup

This tape rotation scheme simply involves doing a Normal backup every day. Although the Son scheme is simple to manage, backing up with a single tape is not an effective backup strategy due to the fact that magnetic media eventually wears out after many uses and the data you can restore only dates back to your last backup.

Father/Son Scheme

Number of tapes required: 6

Maximum Storage life: Two weeks

The Father/Son tape rotation scheme uses a combination of Normal and Incremental backups for a two week schedule.

In the Father/Son scheme, four tapes are used Monday through Thursday for Incremental or Differential backups. The other two tapes containing Normal backups are rotated out and stored off-site every Friday.

The Father/Son scheme is easy to manage and allows you to keep data longer than the "Son" scheme.

Note: If you choose to perform Differential backups, you can use 3 tapes instead of six. For example, you can perform Differential backups with Tape 1 on Monday through Thursday, and use Tapes 2 and 3 for your Friday Normal backups.

To implement the Father/Son scheme, perform the following steps:

1. Label your tapes and perform a Normal backup on Tape 5 (Incremental) or Tape 3 (Differential) on Friday.

2. Follow the schedule shown above for performing backups Monday through Thursday.

3. Rotate tapes 5 and 6 (Incremental) or 2 and 3 (Differential) off-site for maximum protection.

Grandfather Scheme

Number of tapes required: 19

Maximum Storage life: One Year

The Grandfather scheme is one of the most common tape rotation schemes. It is simple to manage and comprehensive enough to find files easily when they need to be restored.

In the Grandfather scheme, four tapes are used Monday through Thursday for Incremental backups. Another three tapes are used every Friday for Normal backups. The remaining 12 tapes are used for monthly Normal backups (January through December) and are kept off-site.

The Grandfather scheme is recommended because it offers a good tape number to storage life ratio (19 tapes/1 year). It is also easy to modify should you want to incorporate more tapes. For example, you could perform a Normal backup on the last Saturday of the month to store permanently.

Ten Tape Scheme

Number of tapes required: 10

Maximum Storage life: 12 weeks

Some tape rotation schemes result in excessive wear on the tapes that are used most often in the schedule. For example, a scheme may require the same four tapes to be used for Incremental backups on Monday through Thursday, every week. The Ten Tape scheme eliminates this by rotating tapes in a way that allows each tape to be used the same number of times over a 40 week period.

The cycle begins with a Normal backup on each Friday, and Incremental backups Monday through Thursday. On the fourth Friday of each four-week cycle, a Normal back up is performed and rotated off-site.

The scheme is divided into ten, four week intervals. The same four tapes are used Monday through Thursday in a given cycle, but change the next cycle. A different tape is used each Friday of the four-week cycle.

When you first implement the Ten Tape scheme, you will need to perform a Normal backup on Tape 10 before backing up to Tape 1 on Monday. This will ensure that you have a four-week-old copy of your data at the end of the first four week cycle.

The main benefit of the Ten Tape scheme is that all tapes are used equally during the cycle. This scheme is more difficult to manage than others described in this chapter. Although less tapes are required than the Grandfather scheme, storage life is reduced to 12 weeks.

Bernard works for Neustro the authors of NeuQs Free Help Desk.