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Re: A Very Bad umount




On Tuesday 11 September 2018 15:28:30 Martin McCormick wrote:

[...]

>        Any constructive ideas are appreciated.  If I left the
> drives mounted all the time, there would be no spew but since
> these are backup drives, having them mounted all the time is
> quite risky.
>
> Martin McCormick WB5AGZ

Why should you call that risky? I have been using amanda for my backups 
with quite a menagerie of media since 1998. On 4 different boxes as I 
built newer, faster ones over the years.

Most recently like 2 weeks back, I retired the drive I had been using for 
virtual tapes for the last 77 thousand spinning hours in favor of a new 
one twice the size. It had 25 re-allocated sectors the first time I 
checked it, at about 3k spinning hours. It was still showing that same 
25 re-allocated sectors the day I pulled it out as it was not big 
enough, hovering at around 90% capacity for the last year.

Not once in all those mounted and spinning hours, has it had even a hint 
of a problem because its mounted 24/7/365 minus a few seconds for my 
backup generator to start, which averages around 4x a year.

I used to worry about it, but HD's that aren't ever unmounted and spun 
down suffer far less damage from parking the heads on a still moving 
platter when the cushioning air film collapses as they stop, and 
dragging on that same platter for at least a turn during the spin up.

IMO the power savings from spinning down when not in active use, do not 
compensate for the increased failure rate you'll get under stop and 
start conditions.

-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>