Berkey B Walker wrote:
quoted text
>
>
> Mikael Abrahamsson wrote:
>> On Wed, 21 Apr 2010, Bill Davidsen wrote:
>>
>>> I hear this said, but I don't have any data to back it up. Drive 
>>> vendors aren't stupid, so if the parking feature is likely to cause 
>>> premature failures under warranty, I would expect that the feature 
>>> would not be there, or that the drive would be made more robust. 
>>> Maybe I have too much faith in greed as a design goal, but I have to 
>>> wonder if load cycles are as destructive as seems to be the assumption.
>>
>> What I think people are worried about is that a drive might have X 
>> load/unload cycles in the data sheet (300k or 600k seem to be normal 
>> figures) and reaching this in 1-2 years of "normal" (according to the 
>> user who is running it 24/7) might be worrying (and understandably so).
>>
>> Otoh these drives seem to be designed for desktop 8 hour per day use, 
>> so running them as a 24/7 fileserver under linux is not what they 
>> were designed for. I have no idea what will happen when the 
>> load/unload cycles goes over the data sheet number, but my guess is 
>> that it was put there for a reason.
>>
>>> I'd love to find some real data, anecdotal stories about older 
>>> drives are not overly helpful. Clearly there is a trade-off between 
>>> energy saving, response, and durability, I just don't have any data 
>>> from a large population of new (green) drives.
>>
>> My personal experience from the WD20EADS drives is that around 40% of 
>> them failed within the first year of operation. This is not from a 
>> large population of drives though and wasn't due to load/unload 
>> cycles. I had no problem getting them replaced under warranty, but 
>> I'm running RAID6 nowadays :P
>>
> Sorry, you sound like a factory droid.  *I* see no reason for early 
> failure besides cheap mat'ls in construction.  Were these assertations 
> of short life to be true, I would campaign against the drive maker.  
> (I think that they are just normalizing failure rate against warranty 
> claims)  Buy good stuff.  I *wish* I could define the term by mfg. It 
> seems Seagate, & WD don't hack it.  The Japanese drives did, but since 
> the $ dropped -
>
Let's see, first you put my name on something I was quoting (with 
attribution), delete the correct name of the person you are quoting, and 
then call me a "factory droid." So I have some idea of your attention to 
detail. Second, the short term failure rates are influenced by 
components delivered, assembly, and treatment in shipping. So assembly 
is controlled by the vendor, parts are influenced by supplier selected, 
and delivery treatment is usually selected by the retailer. A local 
clone maker found that delicate parts delivered on Wednesday had a 
higher infant mortality that other days. Regular driver had Wednesday 
off, sub thought "drop ship" was an unloading method, perhaps.

quoted text
> One thing seemingly missed is the relationship between storage density 
> and drive temp.variations..  Hard drive mfgs are going to be in deep 
> doodoo when the SSD folks get price/perf in the lead lane.  This year, 
> I predict.  And maybe another 2 for long term reliability to be in the 
> lead..
>
I think you're an optimist on cost equality, people are changing to 
green drives which are generally slower due to spin down or lower rpm, 
because the cost of power and cooling is important. It's not clear if 
current SSD tech will be around in five years, because there are new 
technologies coming which are inherently far more stable for multiple 
writes. The spinning platter may be ending, but the replacement is not 
in sight. In ten years I doubt current SSD tech will be in use, replaced 
by phase change, optical isomers, electron spin, or something still in a 
lab. And the deployment of user visible large sectors (write chunks, 
whatever) is not clear, if the next tech will work just as well with 
smaller sectors, this may become a moot point.

quoted text
> I believe that many [most?] RAID users are looking for results (long 
> term archival) that are not intended in the design.We are about 2 
> generations away from that being a reality - I think..  For other 
> users, I would suggest a mirror machine. with both machines being 
> scrubbed daily, and media being dissimilar in mfg and mfg date.
>
It's not clear that date of manufacture is particularly critical, while 
date of deployment (in-use hours), probably is. But looking at the 
Google disk paper, a crate of drives from the same batch doesn't all 
drop dead at once, or close to it, so age in service is a factor, but 
not likely a critical factor.
quoted text
> I can't wait until Neil gets to (has to) play/work with the coming 
> tech. Neat things are coming.
>
I would rather see some of the many things on the "someday list" get 
implemented. It's more fun to play with new stuff than polish off the 
uglies in the old, but the uglies are still there.

-- 
Bill Davidsen <davidsen@tmr.com>
  "We can't solve today's problems by using the same thinking we
   used in creating them." - Einstein

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