[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: A question about deleting a big file structure from a big disk in Jessie: Why does this work? I'm really worried.

On 20150403_1501-0600, Bob Proulx wrote:
> Paul E Condon wrote:
> > David Wright wrote:
> > > I'm not so unlucky as Bob appears to be (he says, touching wood), but
> > 
> > I think Bob came to his conclusion during a previous period of
> > instability in Debian,
> It could also be that I was unlucky in my purchase of cheap USB disk
> enclosures.  Which is why I was careful to relate my experience but
> not cast blame.  Your experiences and others may very well be
> different!  You will have different hardware at the least.  That will
> make a big difference.  I encourage everyone to generate their own
> experience and collect and report the data from it.  It is obvious
> what I am thinking but that doesn't mean it is correct.  I am simply
> communicating in what I hope to be a helpful way.
> Also I know the USB interface is terrible.  I have had the fortune not
> to need to develop on it directly but I have worked with others who
> have had to deal with it in great detail.  Everyone always says the
> same thing.  People who work at the low level USB always report that
> it is a terrible standard.  And yet it has arrived as the defacto
> interconnect used everywhere.  Sigh.  We are going to need to be using
> it for many years.
> I do pause for thought when people talk about file system and usb
> problems "in Debian" as if Debian is the upstream for it.  For the
> most part this would be "in Linux" (unless one was a kfreebsd user).
> Although Debian does have patches for the Linux kernel as far as I can
> see every attempt is made to stick with upstream for the main
> functionality as much as possible.  No one wants to fork and maintain
> critical functionality such as this.  If I had read "a previous period
> of instability in Linux" I think that would have been more accurate.
> Yet the Debian Stable kernels have been selected versions of the Linux
> kernel selected for their stability.  And I had no other flakiness
> noticed.
> That is why I blame my cheap hardware.  And I emphasize cheap because
> literally I can't remember spending more than $20 for any one of my
> USB disk enclosures.  It is a "Market for Lemons".
>   http://en.wikipedia.org/wiki/The_Market_for_Lemons
> > but rather than start an argument that can only degenerate trying to
> > score debating point, I want to gather more date.
> I hope we have a pleasant discourse concerning it.  Out of the
> collected experience I hope we can deduce the best ways to deal with
> these problems.  Hopefully no arguments between us.
> > Bob has already helped me by making a truly useful suggestion,
> > for which I thank him.
> You are most welcome for the hints!  Small and insignificant though
> they may be.
> Bob

On rereading my message, I can see why you are unhappy and offended.

My intent in specifying Debian was to single it out as a place on the
web where rational and knowledgeable people are found, yourself

Between making ill advised posts here, I have been searching the web.
I found two sources that I wish had known about, but didn't.

One is the Backblaze.com web site. Their marketing actually contains
some real technical information on modern HD technology.

And an article in Wikipedia on the history of disk storage:
(http://en.wikipedia.org/wiki/Hard_disk_drive) and other articles that
are linked from there. I learned things that you might think everyone
knows, but I didn't.

For instance, it is known that HDD failure rates do not have 'infant
mortality' (tendency to fail when first put into service) nor
'senility' (a tendency to fail late in life, after a long period of
reliable service).

And, the newer high information density drives all have a supply of
reserve sectors which they use to automatically replace sectors that
are showing signs of incipient failure.

All of the disks in USB packaging that I have had are ones for which
these facts apply. If one is gathering the right data while using
them, one can predictably when they cannot continue to serve, that is
when, for each disk individually, its supply of reserve sectors runs
out. Other random failures can shorten the life to something less can
cause failure when there is still a supply of 'reserve' sectors.

The technical basis of the Backblaze business monitoring all the spinning
reserve (which is a borrowed technical term from the electrical power
industry where it means a dynamo that is already spinning but is not
actually delivering power to the grid).

I certainly wasn't keeping records of HD performance the way Backblase
says they do. I am rethinking. I think I need to be quiet for awhile.

Best regards,
Paul E Condon           

Reply to: