O potrzebie robienia kopii zapasowych

Po paru ostatnich przypadkach utraty danych (padnięty dysk; padnięta płyta główna; nagłe wyłączenie zasilania) w moim otoczeniu pragnę przytoczyć kilka prawd o kopiach zapasowych:

I. Ludzie dzielą się na dwie grupy - tych, którzy robią kopie zapasowe i tych, którzy będą je robić.

II. Yesterday

Yesterday,
All those backups seemed a waste of pay.
Now my source files have all gone away.
Oh I believe in yesterday.

Suddenly,
There's not half the files there used to be,
And there's a milestone hanging over me.
The system crashed so suddenly.

I pushed something wrong
What it was I could not say.
Now all my data's gone
and I long for yesterday-ay-ay-ay.

Yesterday,
The need for back-ups seemed so far away.
I knew my data was all here to stay,
Now I believe in yesterday.

III. Tao of backup

1. Coverage

The novice asked the backup master which files he should backup.
The master said: "Even as a shepherd watches over all the sheep in his flock, and the lioness watches over all her cubs, so must you backup every file on your care, no matter how lowly. For even the smallest file can take days to recreate."
The novice said: "I will save my working files, but not my system and application files, as they can be always be reinstalled from their distribution disks."
The master made no reply.
The next day, the novice's disk crashed. Three days later, the novice was still reinstalling software.

2. Frequency

The novice asked the backup master: "How often should I backup my files? It has been a month since my last backup."
The master replied: "Just as night follows day, and Autumn follows Summer, so should backups follow work. As you work, so should you backup that work."
The novice said: "I work each day".
The master replied: "Then you should backup each day".
The novice replied: "I agree, but right now I haven't got time to make a backup, as I have too much work to do."
Upon hearing this, the master fell silent.

3. Separation

The novice asked a backup master: "Now that I regularly backup all my files, am I enlightened to the Tao of Backup?"
The master replied: "By regularly backing up all your files you are on the path to enlightenment, but you will never achieve enlightenment until you scatter your backups to the four corners of the earth. Does the dandelion drop all its seeds at the base of its stalk? Does the cuckoo lay its eggs in one nest? So long as your backups are in one place, you are vulnerable to the fortunes of the world."
But the novice did not listen, and that night the building burnt down, destroying the novice's computer and all his backup tapes. The novice, went to the master and said: "Master, I have lost all of my data. What shall I do?"
The master said, "Do not despair, for yesterday I took one of your backup tapes and posted it to my brother in China. He will return it."
It was only later that he told the novice that he had posted it by sea mail.

4. History

The novice took an old backup tape to the backup master and asked: "Master, this tape is six months old. If I am to achieve oneness with the Earth, is it not right that it be re-used?"
The master took the tape and said: "I will re-use it. Now, quickly, go and examine your disk drive."
The novice examined his disk and discovered that a virus had corrupted hundreds of important, but rarely-used files. He loaded a day-old backup, but found that those files were corrupted too.
He loaded the week-old backup, but it was the same. Eventually, he realized that the virus had struck four months before. He returned to the master and said: "Master, you have the only uncorrupted copy!"
But the master had already overwritten it with a copy of DOOM.
The master said: "Just as we respect and care for our ancestors, so we must respect and care for our old backups, for one day they may achieve great glory."

5. Testing

The novice asked the backup master: "Master, now that my backups have good coverage, are taken frequently, are archived, and are distributed to the four corners of the earth, I have supreme confidence in them. Have I achieved enlightenment? Surely now I comprehend the Tao Of Backup?"
The master paused for one minute, then suddenly produced an axe and smashed the novice's disk drive to pieces. Calmly he said: "To believe in one's backups is one thing. To have to use them is another."
The novice looked very worried.

6. Security

The backup master was visiting the novice who had just finished installing a network security system for his company.
"See", said the novice, "we have total security here. We have installed the most stringent Internet firewall. All of our staff have been trained to use obscure passwords and not to divulge them to anyone. We monitor all network traffic and all our email is encrypted. Truly our data is safe from disclosure."
The master fell silent, but on his way out he pocketed a 20 Gigabyte corporate backup tape that was lying around.
Later he posted it to the novice.

7. Integrity

The novice was growing impatient on the road to enlightenment. "Master, as a follower of the Tao, I am taking regular backups of all my files. I am archiving them securely offsite, and testing them using Veracity. Surely, master, I am enlightened now?"
The backup master said only: "You will not achieve enlightenment until you control the integrity of your data, for a copy is useless if the original is corrupt. What use is a mirror if we cannot see? What use is an echo if we cannot hear?" But the novice did not understand.
Later the novice returned. "Master," he said, "a cracker on the Internet penetrated my network six months ago and has been corrupting random files ever since. These hundreds of corrupted files have been flowing through my backup system. Now I do not know which files are clean and which are not. I do not know which backups hold the latest clean copy of each file. What should I do?"
But the master was silent.
On the other side of the world, the cracker laughed.

Epilogue

The novice had just finished testing a backup of all his files, which he was now monitoring with Veracity. It was the fifth backup that week, and he had tested the backup by restoring it and checking the restored data with Veracity before taking it to a locked cabinet offsite to be stored with other backups made over the previous few months. The novice said "Now that I have coverage, frequency, separation, history, testing, security, and integrity, surely I have achieved enlightenment?"
The master said: "You are not yet enlightened, but you are on the final steps of the path to enlightenment. The next step is to buy some more copies of Veracity".
The novice became suspicious and said: "Master, is all this 'Tao of Backup' stuff just so you can sell more copies of Veracity?"
The master said: "Now you are truly enlightened."

Autorzy powyższych tekstów są mi niestety nieznani, aczkolwiek chętnie oddałbym im należne honory.