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Re: [ARSCLIST] Suggestions needed re: crashed disk drive recovery

Hey Dave,

Sounds like a pretty good solution you've designed for what I imagine
you have for your budget. The one thing I'd add in a file-based shop is
some sort of tape (preferably LTO3/4) backup system for your SAN. Even
with good cheap disk backup, your overall cost per MB will be lower with
tape, particularly if your archive grows into the multi terabyte range.
You're looking at roughly $50/800GB tape (or $0.06/GB) plus the cost of
a $1-3K for a new drive or small library. If you go back to LTO-3 or are
willing to buy used, things get much cheaper.

The tapes can sit on a shelf consuming no energy and with no moving
parts to wear down. Plus LTO is an open standard with decent longevity
statistics available, built-in data verification on writing, and
backwards compatibility mandated for future versions (so you shouldn't
have a hard time finding a tape drive 10 years from now which will read
your tapes).  Additionally, there are a number of affordable or open
source backup software suites available which are compatible with Mac,
Windows, and Unix and which write to open data formats on the tape,
thereby not tying you to a particular vendor over time.



On Fri, Dec 19, 2008 at 01:31:47PM -0500, Dave Nolan wrote:
> Just a note that I had not seen mentioned here - and that would be the 
> choice of drives for use as backup in the first place.
> I am only speaking from personal experience, and I would be very interested 
> in hearing what other people have to say about the subject, and whether 
> they think that our approach at the 92nd St. Y has any plusses or minuses.
> For primary storage, we are using a series of RAID-5 formatted SAN units 
> from Studio Network Solutions, which uses their SanMP software to "fool" 
> Pro Tools (which does not like RAID).  This particular solution is 
> definitely expensive for most smaller institutions (in the neighborhood of 
> $6.70 per GB raw, closer to $10.00/GB effective with RAID-5 striping), but 
> when you consider that we have had several drive failures over the past 3 
> years, and every single one of them could be quickly recovered from the 
> remaining drives in the RAID array, you could make the argument that we 
> have at least come out even in terms of cost - especially when compared to 
> the prices I have been quoted for outsourced data recovery services.  
> One also has to consider that the costs of blank media in the recent analog 
> past were at least as expensive as going with an Enterprise-class SAN 
> system.  20 or so years ago, I was paying $10-$15 per reel of 1/4" tape 
> holding either 30 or 60 minutes of audio.  If you adjust that for inflation 
> ($10.00 in 1985 now equals roughly $20.00 in 2008), one can make the 
> argument that the cost per recorded hour of 2-channel audio at 24/96 on a 
> SAN is still cheaper than recording the same audio 24 years ago to analog 
> 1/4" tape at 15ips (or even at 7.5ips for that matter).  
> For backups, we are using Glyph GT-Key drives.  These are also somewhat 
> more expensive than your run-of-the-mill Lacie from Staples (about $.60/GB 
> when you buy their 1TB drives), but what you are getting when you buy a 
> Glyph drive is a free data recovery service that has saved my behind 
> personally twice in the past year.  No questions asked, no charge, and they 
> had the drive back to me in 3 business days both times with 100% of the 
> data recovered.  Again, not as cheap as a $.10/GB drive from Staples, but 
> lightyears cheaper if and when you should ever run into a problem.
> Another factor that I have not seen discussed here (apologies if I have 
> missed any previous mentions) is the need to calculate your "MTBF" - or 
> Mean Time Between Failure for the drives in your system.  The fact is, 
> especially if you have a large number of spinning discs, you WILL have 
> drives fail eventually.  There was some interesting information on 
> assessing your probable risk of disc failure from Google a little less than 
> 2 years ago : 
> http://storagemojo.com/2007/02/19/googles-disk-failure-experience/ 
> http://labs.google.com/papers/disk_failures.pdf
> - probably more applicable to institutional archives with large numbers of 
> discs - but still useful in assessing your risk even if all you have is a 
> small number of drives in a relatively small system.  
> Obviously this doesn't help in the short term with an existing drive 
> failure problem such as Richard has described here, but my approach at the 
> 92nd Street Y has been to build safety and redundancy into our system, with 
> the knowledge that drive failures are a fact of life and have to be planned 
> for as part of any IT-based archive project.
> Again - I would be very interested to hear what others have to say on the 
> subject.  As with many underresourced media archives, I am a one-man shop 
> who is making a lot of this up as I go along, and am by no means a real IT 
> or data management expert.
> dave nolan
> 92nd St. Y
> nyc
> p.s. - Just for the record, I get no promotional consideration from SNS or 
> Glyph-tech.  All I get from them is good-quality working equipment that has 
> repeatedly saved my sorry behind in assorted inevitable cases of drive 
> failure.
> dn
> ***************************************************
> On Wed, 17 Dec 2008 20:17:38 -0500, Richard L. Hess 
> <arclists@xxxxxxxxxxxxxxx> wrote:
> >First of all, sorry for the cross-posting...
> >
> >I am beside myself. A non-profit heritage site 
> >that I'm peripherally involved with has had a 
> >disk crash and they then found out that their 
> >backup system has not been working for three 
> >years...although it was religiously taken off-site daily for three years!
> >
> >I had nothing to do with it, but one person/firm 
> >basically told them to forget about the 
> >recovery?that they were likely to get only a few 
> >percent at best--and if anything was retreived 
> >they'd owe the full fee of $3000.
> >
> >I'm hoping to have a meeting with some of the 
> >people who know something about the system and 
> >the problem right after Christmas and the key 
> >piece of information I need to help them is a 
> >short list of drive recovery vendors, especially in Canada.
> >
> >I suspect that no one on these lists have had any 
> >first-hand experience with the need for 
> >this...you're all too careful about backups, and 
> >that is fortunate!!! But maybe you helped someone with their laptop, etc.
> >
> >I can do a Google search, but I'm hoping that 
> >someone knows someone who has had data recovered 
> >(or attempted it) from a crashed hard drive and 
> >can provide an informed perspective about the 
> >process before we dump kilobucks on it.
> >
> >If you've had recovery from a crashed RAID set, 
> >I'd like to hear about that as well, as I don't 
> >think it's a RAID set, but it could be. The more 
> >info I have going into this, the better.
> >
> >It's probably better if you respond directly to 
> >me at mailto:richard@xxxxxxxxxxxxxxx and I can 
> >write a summary piece to post back--if you'd 
> >prefer to be confidential, please let me know.
> >
> >Thanks a lot and Happy Holidays!!!
> >
> >Cheers,
> >
> >Richard
> >
> >Richard L. Hess                   email: richard@xxxxxxxxxxxxxxx
> >Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
> >Detailed contact information: http://www.richardhess.com/tape/contact.htm
> >Quality tape transfers -- even from hard-to-play tapes. 
> >========================================================================


A boast of "I have beens,"   | Daniel G. Epstein
quoted from foolscap tomes,  | Owner/Systems Engineer
is a shadow brushed away     |
by an acorn from an oak tree | Rootlike Technologies, Inc.
or a salmon in a pool.       | http://www.rootlike.com/

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