Luminous Landscape Forum
Equipment & Techniques => Computers & Peripherals => Topic started by: DeeJay on January 19, 2011, 07:11:43 pm
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Hi All,
Just wondering if anyone knows how long an unused hard drive will last for? Googling the matter returns mixed results and certainly nothing definitive or seemingly reliable.
I'm wondering about my backups, and 2nd backups. I wonder how reliable it all is.
Thanks,
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Bad News: basically in a year or so the magnetic information on an unused HD will start to evaporate. The drives should be 'refreshed' regularly to prevent data loss.
Good news: read more on this here (http://www.larryjordan.biz/articles/lj_hard_disk_warning.html)
If you are on a Mac there is a simple Apple Script written that really helps execute the drive refresh. Read about that and download the script, here (http://www.larryjordan.biz/goodies/blog.html). Scroll down to the entry entitled: Refreshing Hard Drives Revisited
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"Bad News: basically in a year or so the magnetic information on an unused HD will start to evaporate. The drives should be 'refreshed' regularly to prevent data loss."
I really don't know what the answer is, but I do know this, recently I decided to buy a Vantec
http://www.vantecusa.com/en/product/view_detail/266
Mainly because I had a hard drive from an IMac I hadn't backed up go south on me. Apple wanted to send it to one of their authorized data recovery centers, I called and they wanted $2500-$4000 to recover the date, so I put the hard drive in a box and put it in storage for about 1.5-2 years. I bought one of the $20.00 Vantec units, hooked up my hard drive, plugged it into my PC and recovered all my data. I then decided to take a bunch (10+) of hard drives I had from about 10 years ago and I was able to recover all the data from all the drives. So if the data starts to evaporate from a hard drive within a year, consider me the luckiest bastard on earth.
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Thanks for the links, an interesting read that seems reliable, and I have to say a little shocking! I have hard drives that I hadn't touched for 5 years that were perfectly fine. I've been using a FW800 Sata Dock for hard drives which is really convenient for backups. Guess I need to diarize a couple days a year to refresh these backups.
Thanks for the info.
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Bad News: basically in a year or so the magnetic information on an unused HD will start to evaporate. The drives should be 'refreshed' regularly to prevent data loss.
Chris, I think the official term is "bit rot"...
:~)
Also, the hardest thing on electronics is the first rush of current through the system when it's turned on. That's when some bad things can happen to drives and components fail. The next most likely problem is directory corruption-which can be easier to recover data from. In general if you are buying the high quality (non-OEM) with a minimum 3 year and ideally 5 year warrantee, the MTBF is a much larger number and thus more reliable. You do tend to get what you pay for.
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The technique used in the scripts Chris refers to essentially copies all the data on a drive to a nul device. Reading data on a hard drive refreshes it. Interestingly Windows does not give you a nul block device you can copy to! MS has this "workaround", which for our needs is complety useless:
http://support.microsoft.com/kb/319137
My practice is to simply copy archive drive to new drive every 2nd year, and yes, i reuse drives for this purpose
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Reading data on a hard drive refreshes it.
Seems counter-intuitive to me. Why and how does reading refresh?
Jeremy
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So -
If you had a USB external HD which had been in a cupboard for a year or so, if you simply plugged it in to a live PC and left it attached for a day, would the OS automatically check the drive and refresh any bad sectors etc?
John
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The technique used in the scripts Chris refers to essentially copies all the data on a drive to a nul device...
Does this script the same as doing a complete surface scan..? Reading the complete harddisk block to block as is possible with Tech Tool Pro ?
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Does this script the same as doing a complete surface scan..? Reading the complete harddisk block to block as is possible with Tech Tool Pro ?
Yes
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Seems counter-intuitive to me. Why and how does reading refresh?
Not counter-intuitive at all - HDDs rely on magnetism to read/write data, and reading it refreshes it.
Whether that happens and has a meaningful impact on drive longevity is another matter ;)
To contribute to the black magic and speculation, I've read on the internets that the main contributor to HDD failure for idle (unplugged) drives is that the lubricants don't work as well anymore.
And another black magic trick for dead drives: stick them in a freezer for an hour and it might wake up for long enough to be able to pull data off it. This is counter-intuitive given the above point, but I've read enough anecdotes of successes to have tried it myself - to no success.
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And another black magic trick for dead drives: stick them in a freezer for an hour and it might wake up for long enough to be able to pull data off it. This is counter-intuitive given the above point, but I've read enough anecdotes of successes to have tried it myself - to no success.
Not sure about the freezer cause that's pretty cold for the operating ranges of HDs, but I did recover data off a laptop whose drive was overheating and then shutting down by putting the laptop in the refrigerator which slowed down the overheating enough that I could get the data off the drive. As I remember, I could get about 15-20 minutes of copy time until it heated up enough to lock up the laptop. Then I had to let it sit shut down for a few hours to cool. I recall it took the better part of a day to get everything off the drive. That's useful for a situation where the drive itself is overheating...won't help other drive issues though.
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Seems counter-intuitive to me. Why and how does reading refresh?
Jeremy
Modern drive heads are down to reading quantum levels, at this level you can't observe something without affecting it; you have to read and refesh what is there
https://www1.hitachigst.com/hdd/technolo/gmr/gmr.htm
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I've actually did the freezer trick long ago on an ancient scsi drive - the explanation the seagate tech gave me was the aluminum platter shrinking in size enough to allow acceptable head/track alignment.
More recently i recovered some files from a notebook drive, but in the case i suspect a component trace on the controller opening up as the drive achieved operating temperature.....
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I want to know why all you people aren't backing up your HDs? You should never have to put it in the freezer or plug it into an external source in order to get the data have, I thought this only happened to me! ;D
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I want to know why all you people aren't backing up your HDs?
Oh, I have backups of backups for mission critical workstations...it seems like it's the less than mission critical drives like on a laptop or a 2nd workstation sometimes falls through the cracks...my most recent problem was that on my 2nd machine (which houses email and iTunes music) hadn't been backed up for a month. So, of course, THAT'S the drive that got a corrupted directory that couldn't mount of boot. I got everything back through a software tool and the fridge wouldn't have mattered since the drive was ok but the directory was corrupted. I mean, it wouldn't have been a total disaster...except for losing a month of email and about 100 iTunes tunes...
Lots of drives, lots of machines...sometimes things fall into the cracks. Those will be the drives that blow up–thanks to Murphy's law.
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Jeff you are a bad man! ;) I always back up now, I at one time got lazy, but now it's a daily ritual. Aren't negatives GREAT? I mean we don't have to back them up, they are always there. Sometimes I wonder if digital imaging is easier or more complicated or both?
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Aren't negatives GREAT? I mean we don't have to back them up, they are always there.
What, you've never had a basement flood?
I've prolly spent more time recovering negs at risk then trying to recover digital objects...but it may be close to a toss up. Kinda like 6 of one, 1/2 dozen of the other really...
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"What, you've never had a basement flood?"
A couple times, however the negatives were high enough off the ground in a nice cabinet. I even have my father's negatives from the 30s-80s. I guess there's a part of me that misses that, I still have every negative / slide from every photo I have ever taken and not one has ever become corrupted or gone bad. I don't need 2-3 backups, though I have scanned most of them into my computer. Label the negatives, put them away and one could forget about them, today we have to remember to back up and make a back up of the back up and then we can't forget about the files because media goes bad, so we need to keep moving the files from drive to drive............................and so on and so forth.
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That's true, but if the worst happens to the place where the negatives are stored - they're gone. If you have offsite backups of your digitals, they're all good. They also take up less space :-)
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No doubt about it you are right. I know a couple people who lost everything in house fires and it's amazing that photographs are the items they miss most, just about everything else is replaceable.
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Modern drive heads are down to reading quantum levels, at this level you can't observe something without affecting it; you have to read and refesh what is there
https://www1.hitachigst.com/hdd/technolo/gmr/gmr.htm
To quote the article Chris mentioned: "So...in the interest of checking things out, simply reading every sector on a disk actually is preventative; if the controller within the disk detects any marginal data in either the servo tracks or the data bits recorded on the surface, the controller will automatically rewrite the data to the sector.". I.e. the refresh/rewrite is the exception and not the rule.
If each read operation would require a refresh reading from a hdisk couldn't be faster than writing (but it is).
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If each read operation would require a refresh reading from a hdisk couldn't be faster than writing (but it is).
Actually, I'm the one that posted that link. You are correct in that an explicit write does not take place unless an error is detected, in fact all modern drives have separate read and write heads. What does take place is a refresh (via bias) of the magnetic domain in the area where the data is located - the exact method depends on the technology involved. The hitachi/ibm paper is actually pretty dated - i remember reading a great description of more current technologies recently, I'll update this post with a better link, describing vertical recording methods as soon as i can locate it
regards - John
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I'm a Windows guy - please, no comments! - obviously I can't use the Apple script. Does anybody now if defragging a drive might have the same effect and wake those pixels up every few months or so? The big question in my mind, I'm not a techie, so I don't know, is what action occurs during this process and is that action sufficient if the drive really doesn't need defragging? Thanks.
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Wondering also...
I am using a Sata Dock to backup to bare Sata drives. It's a very effective solution.
Wondering though, as each drive has a high powered magnet inside, is it OK to file the drives away next to each other? or will the magnet effect the data of the drive next to it?
Thanks,
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I'm a Windows guy - please, no comments! - obviously I can't use the Apple script. Does anybody now if defragging a drive might have the same effect and wake those pixels up every few months or so? The big question in my mind, I'm not a techie, so I don't know, is what action occurs during this process and is that action sufficient if the drive really doesn't need defragging? Thanks.
I suspect not. A defragmentor starts by looking at the directories and the individual files' block lists. If they indicate that there's no, or no significant, fragmentation, the app won't do anything more and the vast bulk of the disk will remain unread. It's only if it has to move files around that it will look at the rest of the disk.
Jeremy
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Wondering though, as each drive has a high powered magnet inside, is it OK to file the drives away next to each other?
Just thinking out loud, but in a computer, HDD are generally set very close to each other without much if any side effects known?
With a dock (a solution I'm considering too), I'd be extra cautious about anything getting in the HDD connectors (just as with a CF card).
Otherwise, magnetism is kinda "enclosed" in the HDD box, and shoudn't be a problem as long as you don't live in an electric power plant I'd think.
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Thanks, yeah that's what I was thinking.
I would highly recommend the Sata Dock. It's been a really effective and practical backup plan. I have a Hazel Droplet, it automatically saves the files to two eSata docks for two backup copies. When the disks are full I label them, print the a copy of the finder out and file them away.
I also have time machine running for hourly backups of my working files.
Such a simple and effective solution and bare sata drives are really so cheap these days!
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Yikes! This makes me worry a bit about my archived backups (currently all external hard drives & some DVDs stored in a fireproof safe). Are many of you switching over to a cloud based backup system? If so, how does that work (thousands of GBs of data to upload)? Any recommendations on the best backup solution (physical or virtual)? I have thousands upon thousands of wedding photographs from the years of my photography work that I need to keep safe. Cheers!
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Most "fireproof" safes are rated for paper (ignition point 451f), make sure your safe is rated for media. The safest thing to do is each drive to a fresh one.....
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And another black magic trick for dead drives: stick them in a freezer for an hour and it might wake up for long enough to be able to pull data off it. This is counter-intuitive given the above point, but I've read enough anecdotes of successes to have tried it myself - to no success.
I did this years back on an Ultra-SCSI drive on a Mac, and it worked! ;D
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Just wondering if anyone knows how long an unused hard drive will last for? Googling the matter returns mixed results and certainly nothing definitive or seemingly reliable.
I'm wondering about my backups, and 2nd backups. I wonder how reliable it all is.
Well, nothing lasts forever ... I've recently turned on hard drives that have seen no power in almost 10 years with no problems.