While trying to find more sources for the 'Unplugged hds in a server can fail over time" discussion in this thread, I came across an interesting article (Not claiming the value of the source) that states that the magnetic signal of data on unplugged drives (So if you are using it to archive data for example) will fade over time (The article is claiming 1- 1.5 years)...

 

http://www.larryjordan.biz/hard-disk-warning/

 

I always assumed they would eventually lose data, but 1-1.5 years seems v.short...

Interesting. I typically retire my drives from active service after two or three years and use them for archiving. I seldom restore anything from the archives so I have no idea whether the data is still there. Sounds like they should be checked and/or refreshed every year or so.

That sounds reasonable since the same thing happens to magnetic recording tape. Also the deck plates of the recorders if made of steel can become magnetized aligned with the earths magnetic field from just sitting. I've seen tapes that were stored for a few years get partially erased on a part of the tape that was facing a magnetic source like a speaker or TV, so that once per revolution the sound would fade out and in again. Another thing that happens with tape is magnetic bleed from one layer to the other causing what you may call data corruption.

I archive important data that I may need to go back to as much as I can to DVD-ROM using the best blank media that have proven themselves. So far I can go back about 15 years on DVD and back to about 1996 on CD-ROM and the data is still good.

I have all my backups on drives stored in WiebeTech Drive Boxes

[ http://www.newegg.com/Product/Product.aspx?Item=079-005J-00003 ]

 

... which I keep in a data-rated waterproof, fireproof safe.    I have checksums for all the files on the drives; and once/year I cycle them through an eSATA drive caddy and validate all the checksums -- so every file is read and validated, and the disk's SMART mechanism will automatically refresh any marginal sectors.

 

If you don't trust the SMART system to refresh marginal sectors, an alternative would be to do a Level 3 pass with Spinrite once/year.    This will rewrite EVERY sector on the drive, so it's more thorough than simply letting the SMART subsystem rewrite those that have marginal read levels.

 

But in any event, I agree that an annual pass on the stored disks is a good idea to avoid loss of data due to deterioration of the magnetic signal.

 

 

 

"I read it on the Internet, so it must be true."

 

"I read it on the Internet, so it must be true."

 

Hence my caveat regarding the value of the source... Your statement implies that you don't believe it. Do you happen to have a reputable source for a pro/con argument?

 

I have no bias in either direction, frankly. I'm just hoping to stimulate some non-rhetoric-laced discussion based on credible data (or as credible as the internet can be )...

 

If you don't trust the SMART system to refresh marginal sectors, an alternative would be to do a Level 3 pass with Spinrite once/year.    This will rewrite EVERY sector on the drive, so it's more thorough than simply letting the SMART subsystem rewrite those that have marginal read levels.

 

 

I would love to have that option.  But the current version of SpinRite (6.0) does not work on drives greater than 2.2TB.  In addition, it is extremely slow.  I tried a level 4 pass on a 1.5TB drive once and it took 10 days to complete!!!

 

Given the recording density of current drives, problems are only going to get worse.

 

Gibson is working on an update to 6.0 that should resolve both of the above issues.  But he does seem to get distracted on to other projects/issues way to easily.  Who knows when we will see that 6.1 version.  I would not hold my breath waiting for it.  I do listen to him on Security Now weekly, so if I hear of anything about a new version I will post an update.

I'd forgotten that Spinrite doesn't yet support > 2TB drives.  In fact, the v6.1 upgrade that will provide this isn't likely to be out anytime soon ==> this is the status Steve has for that upgrade:  "... This is not something we have started work on, but it has a high and growing priority. "    Translation:  Spinrite sales are likely low enough these days that there's little motivation to make further upgrades.  It's been a long time since the v6 upgrade (I've had Spinrite since the late 80's, and I believe I got v6 ~ 2005).

 

It'd be nice to see a v6.1 that adds support for modern high-capacity drives, but somehow I don't think that's likely.

 

 

 

 

It'd be nice to see a v6.1 that adds support for modern high-capacity drives, but somehow I don't think that's likely.

 

 

The info on his site is out of date.  You have to listen to his podcasts to get current info.  He is essentially a one man operation, like someone else we know.   He was working on it last summer and had made some significant progress on 6.1 until he got this idea about doing SQRL.

 

http://en.wikipedia.org/wiki/SQRL

 

SpinRite 6.1 got put on hold at that time.  He says he has about wrapped up the SQRL project and will be back working on 6.1 soon.  I will believe it when I see/hear it. 

 

He has recognized the need for the update and has committed to do it.  It will be a free upgrade for licensees of 6.0  If we do eventually get this update, I think it will see significant use in the testing and maintenance of drives to be used with unRAID.  As you probably know, SpinRite is OS agnostic.

"I read it on the Internet, so it must be true."

 

Hence my caveat regarding the value of the source...

My remark was not directed at you [else, I would have quoted you.] (Anyway, you clearly expressed some doubt to the veracity.)

Your statement implies that you don't believe it. Do you happen to have a reputable source for a pro/con argument?

Common sense tells me it is hogwash. If there was an issue, you would have heard about it--and experienced it. The market would never accept such crap (and there would be a specification for it.)

 

--UhClem

 

 

If we do eventually get this update, I think it will see significant use in the testing and maintenance of drives to be used with unRAID.

 

Absolutely.  Nothing tests a drive like a Level 4 or 5 pass with Spinrite -- that does far more read/write ops than a pre-clear (but would also, of course, take far longer)

 

Steve's always been a one-man shop as long as I've known him (I met him a few times in the early 90's),  but (like someone else we know) is very dedicated to his projects and only releases new versions when they're "right".    I'd love to see an updated Spinrite ... but if folks think it was a long time between UnRAID releases -- it's been almost a decade since a new version of Spinrite was released 

 

According to IEEE Transactions April 2010, Larry's unnamed guy is completely incorrect.