HDD conservation 3

[mikeo1313]

I have about 6 HDD's , 3 are used to keep a full backup of everything I have.

I started wondering since I often don't access anything more then a few gigs every month I should keep them powered off to preserve their life.

Is this a good or bad idea as I'm not sure whats the best of both options keep them on even though they hardly get used since MTBF is only related to actual read or writes OR keep them powered off the most I can?

 

[BadBigBen]

since drives are mechanical, they wear when they run...

but also keep in mind that the lubrication can harden when they are not used...

I would conjecture to say, that when you just access them once in a while and keep them off for the rest of the time, that that would prolong the usage of said drives, I've seen drives that where 10 yrs old that still function and I've seen drives 10 days old that just conked out ...

as technology continues to advance, those drives may not be readable in future machines...




Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[goombawaho]

I would wonder why you need three drives for your backup. Why do I care?? Make it simple and try to keep backup on one or two drives that can hold a FULL BACKUP EACH.

Why? Well, the more disks you have spinning, the more likely one is going to fail in any given time period. Thus, if you have a dependency on MORE than one drive to be able to do a full restore, you increase the odds that you won't be able to do it.

In summary, multiple backup devices are okay as long as each can hold a full backup and are not spanned. This was like the old tape backup days. You have six tapes for a full backup. Restoring the whole thing depends on each tape in the set or you would be hosed.

 

[mikeo1313]

@badbigben
sterically hindered polyester (shp) is the lubricant but couldn't find specific details.

@goombawaho
Ok, 2 drives (1 of which has a split partition) are the full backup of the active 3. So I already have my backup drives powered off besides probably synchronizing updates every month or 2, or as needed.

My perspective is I have drives that are powered on(3) & off(2), but even the ones that are typically on I just access about 10-20 gb of data of the aggregate 3tb's in a month's time and considered if they wear as they spin I can even keep those (2 of the 3 active drives) off as my primary os drive has enough free space to cover my temporary usage need.

The factor of the sph hardening is something new to I never considered. Seems like I'll have to call seagate.

 

[BadBigBen]

as far as I remember, HDD's use fluid bearings these days, and the mentioning of hardening may be just a remnant of the old ball bearing that they replaced,,,

but:

Fluid bearings can catastrophically seize under shock situations. Ball bearings deteriorate more gradually and provide acoustic symptoms.

and one should not read to much into the MTBF rate of a drive, as testing is done in a lab before the drive goes into production, but rather look at the AFR of those drives... Interestingly Google did a research back in 2007 on exactly this subject, and it seemed that they preferred Hitachi HDD's... ;-)

AFR

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

Heavy read (16 pages):

Disk failures in the real world:
What does an MTTF of 1,000,000 hours mean to you?

http://www.usenix.org/event/fast07/tech/schroeder/schroeder_html/index.html

Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[mikeo1313]

http://storagemojo.com/2007/02/19/googles-disk-failure-experience/

The 2nd graph of this link, AFR & utilization, did it for me.

 

[goombawaho]

I think all of these graphs and statistics are quite meaningless from a "what does it mean to me standpoint" since all hard drives will eventually fail. Sooner?? Later?? - Who knows. So you need a good backup plan no matter what the age, size, speed and/or utilization of said drives.

That should be the take away lesson.

 

[mikeo1313]

@goombawaho
Great non-point. My back-up plan is good enough was seeking more details more hardware specific.

@badbigben
Here's what Seagate wrote me today regarding shp and powering on a powered off drive.

Thank you for contacting Seagate. Great question! I would recommended going with once a month. There are lots of little factors, especially environmental factors, that can affect that, but a good general period is once a month. A key environmental factor is avoiding situations which might allow for condensation to occur.

If you have any additional questions you may call us during your regional business hours listed below. For your convenience we also have on-line chat assistance.

 

[BadBigBen]

mikeo1313,

thank you for posting back, and very interesting to see what Seagate wrote... ;-) but it does sound like good advice, keep things lubed.

About the moisture there are Silicagel desiccant bags, that come with lots of electronic gear, you could use those with anti-static bags for storage of those drives... JAI...

PS: I am not a great fan of Seagate, when drives went bad they replaced them with refurbished units, two of these refurbished units died within a month, which caused me lots of headaches with some of our customers... that is mainly why I prefer WD (when their units died, I got NEW units as replacement), and Hitachi (haven't had one fail yet)...



Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[goombawaho]

You should listen to the voices of experience.

 

[goombawaho]

You know, I want to add a side question/comment to this that I don't think is going off in a new direction.

BadBigBen mentioned condensation. I always wondered whether that was true. I met a customer once that said they kept their backup portable hard drive OUTSIDE in case the house burned down. And that would be in a norther (cold winter) climate.

Question would be - is there really a condensation worry when they bring that drive in from outside because of the fact that the drive is SEALED (how could moist air get IN in the first place)?

I wasn't sure that I could swear to him that keeping the drive outside was a dumb idea. Any links or documented evidence?

 

[BadBigBen]

Goom,

while within the bag, moisture can creep in and stay in... thus the silica gel bags that you get with lots of HDD's or other electronic gear...

a drive may be cold, e.g. kept in the garage for safe keeping, once taken inside it is obviously colder than the temperatures inside, which will cause condensation to appear... but, this condensation will disappear just as quickly as it appeared, same applies if you breath on a cold window, it will fog up but soon be gone again, as the air reabsorbs the moisture... so, your customer should be fine, as long as he waits a while (10 min. or so) before applying power to said drive...

further reading on the subject, I would conjecture either Thermodynamics or simpler Dew point...


Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[goombawaho]

But how does the dampness get IN?

Interesting concept. I was wondering if there might be little beads of water (dew) forming on the drive when it was brought in and then spinning off the drive (like rain off a tire).

New "off site" backup concept: Dig a hole in the yard and bury your data next to your money that you don't want to put in a bank.

 

[BadBigBen]

>> New "off site" backup concept:

ah, the finer points of sarcasm... he he... ;-)

PS: drives have breathing holes, which are filtered for dust...

Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[goombawaho]

I guess I knew that about the breathing hole because I've seen the little filter when I tore apart some old drives. So that's an avenue for humidity in/humidity out as well as breathing.

 

[DrB0b]

A lot of the drives Ive disassembled have a tiny silica pack in them to alleviate the small amounts of condensation/dampness that will get in....

"You don't know what you got, till its gone..
80's hair band Cinderella or ode to data backups???

 

[goombawaho]

I've never seen that UNLESS it was integrated into the little filter thingy. All very interesting.