How data gets lost
Summary: Our perception of risk and the reality of risk are often two different things. For example, are computer viruses or system glitches more likely to hose your data?
Our perception of risk and the reality of risk are often two different things. For example, are computer viruses or system glitches more likely to hose your data? While viruses get bad press for poor system performance, they aren't very likely to damage your data. Your system, on the other hand . . . .
This is data loss week at Storage Bits. I'll be talking about causes of data loss in some detail, starting today with the general factors and then drilling down into the major cause of data loss problems at the device and system levels.
Hoping for a silver bullet? There isn't one. Backing up your data regularly, either to a local hard drive or to an on-line service such as Carbonite or Mozy is your best bet. I will give you some concrete tips on limiting the damage in the one area you can control: yourself.
There is hope, however, that our systems will start treating our data a lot better than they do today. I'll cover that later this week.
What are the causes of data loss? I had a nice talk with the folks at Kroll Ontrack, the worlds largest data recovery firm. They have some interesting statistics on what actually causes data loss.
| Cause of data loss | Perception | Reality |
| Hardware or system problem | 78% | 56% |
| Human error | 11% | 26% |
| Software corruption or problem | 7% | 9% |
| Computer viruses | 2% | 4% |
| Disaster | 1-2% | 1-2% |
Disk and system problems What is interesting here is that Ontrack's data suggests that we are too quick to blame our systems and not quick enough to blame ourselves. Their experience is that human error is a bigger piece of data loss than we'd like to admit. More on that below.
In general, there is little you can do about hardware or software problems. I use a battery backup unit with a surge protector to keep power clean and steady and maybe that helps.
My major strategy is to backup every day to a local disk. And I backup important files to an online service as well. As long as I've got a credit card to buy another system I can be on line in a couple of hours. And yes, I keep that password with me.
Why do I do both? Because recovery from a local disk is hundreds of times faster than downloading gigabytes over the net. But if a catastrophe happened, at least I still have access to critical data. I also keep a second machine - a notebook - for backup as well.
Panic is a factor in data loss Human error is a major problem in data loss. That shouldn't be a surprise: human error is a major factor in everything.
But there are some common things that people do that make data loss situations worse. When you suspect data loss, follow these simple steps;
- Take a deep breath and stop! Panic is a common reaction, and people do really stupid things. Experienced admins will pull the wrong drive from a RAID array or reformat a drive, destroying all their information. Acting without thinking is dangerous to your data. Stop stressing about the loss and don't do anything to the disk. Better yet, stop using the computer until you have a plan of attack.
- If your disk is making weird noises, normal file recovery software isn't going to work. I've had luck with performing a backup right away after hearing odd noises, but that is a matter of luck.
- If the drive is still spinning and you can't find your data download a data recovery utility onto another computer. Google for "free data recovery software" for some options, including one from Ontrack. The important thing is to download them onto another drive, either on another computer, or onto a USB thumb drive or hard disk. If you don't you could be overwriting the data you are trying to save. It is good practice to save the recovered data to another disk.
If you have some tech moxie you might want to look at free data recovery programs such as NTFS Reader and PC Inspector. Neither is for newbies, so if you don't have a high degree of confidence in your PC ability, get a more knowledgeable friend to help.
If your drive is making grinding noises or has stopped completely, your data can still be recovered, but it will cost you in time and money. Google "disk data recovery" or check the back pages of your favorite PC mag for disk recovery companies.
The Storage Bits take Disk drive life may be a matter of luck, but data loss isn't. You can dramatically improve your odds by backing up your data on a regular basis to a USB or Firewire hard drive. For those whose livelihoods rely on computers, off-site backup is also a good idea, as is a backup computer.
Next: There are 50 ways to lose your data: a catalogue of disk woes.
Comments welcome. I'll update the post if I see a good one.
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Talkback
One of the most frequent data loss problems
My related favorite:
because it is an attachment, it doesn't get saved.
Been bit by that one myself more than once.
Robin
Using Outlook?
ROTFLMAO...
Binary Coded Decimal
Good catch!
Robin
Hmmm...
AND - a web dictionary of abbreviations gave a following entry for ROTFLMAO:
A chatroom abbreviation used mainly by imbeciles, usually in response to something mildly, often very mildly, amusing. People who use this type of shorthand should be avoided like the Spanish flu.
My opinions
When boadband reaches gigabit speeds, maybe. But as long as we're talking magabits, no way. And even then, I worry about them having access to my data. Why should I ever trust these people?
As far as maintenance and repair software goes, I recommend SpinRite. It doesn't cost much and it's worth every penny. If your hard drive is failing, it'll usually keep it up long enough to transfer the data to a new hard drive.
Keep in mind that even if such software "fixes" a hard drive, you should still transfer the information to a new hard drive and throw away the old one! Once a hard drive starts failing, it only gets worse over time - often very quickly. You do [b]not[/b] want to keep using a failing hard drive!
Remember when disposing of any hard drive for a business to follow your business's disposal procedures. If it has sensitive data on it, it should be destroyed before disposal.
Defense in depth
people who work on the web or are highly mobile, online backup is another layer
of protection. <br>
<br>
True, it would take me a few days to download everything I have stored online. But
that is far better than never seeing it again. Most people don't need it, but most of
my work life is online.
<br>
<br>
I don't worry about data security as my data is encrypted on my machine before it
leaves home. Even the storage company doesn't have a key.
<br>
<br>
I've heard good things about SpinRite. Thanks for the tip. <br>
<br>
See <a href="http://blogs.zdnet.com/storage/?p=129" target="_blank">How to
REALLY erase a hard drive</a> to learn about the NIST approved built-in method.
Check out the <a href="http://blogs.zdnet.com/storage/?p=148"
target="_blank">update</a> as well.<br>
<br>
Robin
On-line and others
Regarding those people at services like Mozy sorting our "dirty underware" - I do not care. My financial data are not to be found there, just a collection of writings in a language I doubt they can read. The rest of my data - different images, some music etc. rest on a shelf in a 300 GB portable drive. Which is perfectly enough for me.
My sensitive financial data are the most insecure in case of loss - they are in my memory alone. If I happen to damage THIS hardware, I might be heading right into trouble... ;-)
Online backups are a must to...
Of course, if you cannot decide what data from your 500 GB of data is "critical", then online-backups are not for you.
Regards,
MV
Just a grammar quibble
I know it's frowned upon to put grammar quibbles in a place like this, but this was just too egregious not to say something.
Flames go to /dev/null.
James
Language changes...
A mass noun is one where we don't consider counting the members individually, but rather think of measuring it indirectly, if we consider quantity at all.
We don't say "the sand are sparkling in the sun". But we'd say "the grains of sand are".
So we don't say "the data are" -- we say "the data items are".
And we say "how much data", not "how many data" -- more evidence that it has become a mass noun. "How many data" just doesn't make any sense! 2 trillion what? Characters? Records? Events? Observations? The move to a mass noun was really forced by the structured nature of data; it simply is not amenable to a unique count.
Yes, originally, "data" was the plural of "datum". But that language has been dead for about one thousand years.
If people were in fact talking about the individual data items (the "datums"), then you would be correct. But now when people talk about "data", we are speaking of a large collection, not the content of that collection.
To speak specifically of multiple collections, we have phrases like "data sets". Maybe in the far future, that will evolve into "datas". Hopefully not in my lifetime...
(Feel free to berate me about "hopefully", which makes no grammatical sense to me either, but I still use -- often in sentence fragments....)
It's been my experience that most of the time, when people pop up with things like this, they've simply (subtly) misunderstood the usage in question. I've seen many a professional grammar writer fall into this trap, so you're not alone.
Now for some fun, everyone can chime in, pro and con, with "Hear, Hear, Hear!" or "Here, Here, Here!" -- nearly opposite in meaning, but frequently confused...
(I wonder how much data has been lost writing to /dev/null?)
Bad recovery an extra factor; malware may magnify
So I think we're correct to concentrate on malware, though the recent commercialization of the malware scene may have lulled folks into a false sense of security. The lack of recent data-eating payloads has less to do with the protective abilities of NTFS (read up on Witty, a pure network worm that trashes NTFS from within XP via raw sector writes) than, well, few folks writing that sort of code at the moment.
I'd add an extra category; botched maintenance, and I'd rate that as between 5% and 20%. This escalates a recoverable data loss to a larger unrecoverable one.
For example, I had a client in tears after the Thus Word vir.. uh, "prank macro" payload trashed her data. The details of how Thus works made me fairly confident her data could be recovered, especially as it was off C: on logical drive D:, where there was no other non-data write traffic.
But her "husband's work" had already "fixed the virus" by "just" wiping and re-installing Windows, and had also replaced the partitioning with one big doomed C: volume. They'd thoughtfully wiped the HD before doing this "to be sure the virus was gone", so there was no happy ending.
It was the event that led me to write this...
http://cquirke.mvps.org/9x/recovery.htm
...and you may sense the anger in that writing.
Backup: Hard drive + online
As you note, for recovery, the fast access to the USB-drive is critical. Using an external drive is good, because you can easily move it to another computer for recovery. (But of course, in a pinch you can extract an internal drive, and drop it in a USB case, so internal is an option of you don't like external for one reason or another).
Online is for disaster recovery. Fire. Theft. And for backup or recovery when you're on the road.
Hard drive is for bare-iron recovery.
And yes, you CAN back up many, many gigabytes of data over broadband. The initial backup may take days to accomplish, but unless you're producing many gigabytes per day of new/changed data, it's not really a problem.
Unless you have both, you're not really protected.
But forget anything that's not fully automatic. It's just not going to happen, and you'll be left in the lurch.
online data and security
I'd love to hear any stories... toms@spokesman.com
Use online backups
Thanks
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