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Re: SSD drive reliability.

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On Mon, 16 Jun 2014 10:41:36 +0200, David Brown wrote:

> On 14/06/14 09:50, Charles T. Smith wrote:
>> On Tue, 10 Jun 2014 01:15:14 +0000, Bob Tennent wrote:
>> 
>>> On Tue, 10 Jun 2014 02:01:17 +0100, Måns Rullgård wrote:
>>>  > Bob Tennent <BobT@cs.queensu.ca> writes:
>>>  >
>>>  >> On Tue, 10 Jun 2014 00:57:17 +0100, Måns Rullgård wrote:
>>>  >>  >
>>>  >>  >> SSDs in general are considered to be much more reliable than
>>>  >>  >> HDs.
>>>  >>  >
>>>  >>  > When did this change?
>>>  >>
>>>  >>   "From the data I've seen, client SSD annual failure rates under
>>>  >>   warranty tend to be around 1.5%, while HDDs are near 5%," Chien
>>>  >>   said.
>>>  >
>>>  > How long is the warranty for each?  Does this statistic take into
>>>  > account the vastly different capacities?
>>>
>>> The subject of SSD reliability is rather controversial. As I
>>> suggested, Google "SSD reliabilty" for lots of discussion.
>> 
>> 
>> What's the difference between an SSD and a flash usb stick?  I have
>> tried repeatedly to use flash usb sticks as linux drives, using ext2 as
>> the FS and mounted with the noatime option to avoid too many accesses. 
>> After only a few mounts, these FS always end up corrupted.
>> 
>> The problem with flash is that "checking" them for integrity only
>> decreases their lifetime.
>> 
>> I don't use flash anymore, for anything.
>> 
>> 
> There is a world of difference between the average SSD and the average
> flash stick (though less between the lowest of SSD's and the best of
> flash sticks).
> 
> Flash sticks usually have minimal or no wear levelling, redundancy,
> error checking, sector re-mapping, etc.  Instead of wear levelling, they
> often have special flash for the first few MB's that supports many more
> erase/write cycles - specifically to handle the extra pressure FAT
> places on those sectors.  The rest of the flash is as cheap as possible,
> as is the controller.
> 
> ext2 does not use a FAT - its high-use tables are in different areas of
> the disk, thus you will wear out a USB flash stick faster with ext2 than
> with FAT.
> 
> Flash sticks are also very prone to damage if you are not finished
> writing before you remove them - always umount them (or at least "sync"
> them) before unplugging.  It is not enough just to wait for the led (if
> it has one) to go off.


So, in conclusion - don't use an SSD if you're going to run linux.

As to wear-leveling ... that's presumably in the OS driver.  Maybe.  I 
wonder if any drivers report statistics.

I mean, the very concept of load leveling says everything that needs to 
be said.  What happens to those areas which get reduced usage?  It 
presumably means they've been worn - maybe they still work, but do you 
ever want to use them again?  Which access is going to be the one that 
tips them?

Is flash/SDD a fancy WORM drive?

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Thread

SSD drive reliability. wexfordpress <john@wexfordpress.com> - 2014-06-09 15:49 -0700
  Re: SSD drive reliability. Bob Tennent <BobT@cs.queensu.ca> - 2014-06-09 23:13 +0000
    Re: SSD drive reliability. Måns Rullgård <mans@mansr.com> - 2014-06-10 00:57 +0100
      Re: SSD drive reliability. Bob Tennent <BobT@cs.queensu.ca> - 2014-06-10 00:54 +0000
        Re: SSD drive reliability. Måns Rullgård <mans@mansr.com> - 2014-06-10 02:01 +0100
          Re: SSD drive reliability. Bob Tennent <BobT@cs.queensu.ca> - 2014-06-10 01:15 +0000
            Re: SSD drive reliability. "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2014-06-14 07:50 +0000
              Re: SSD drive reliability. Poutnik <poutnik@privacy.net> - 2014-06-14 10:19 +0200
              Re: SSD drive reliability. "Trevor Hemsley" <Trevor.Hemsley@mytrousers.ntlworld.com> - 2014-06-14 21:10 -0500
                Re: SSD drive reliability. "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2014-06-15 08:48 +0000
              Re: SSD drive reliability. David Brown <david.brown@hesbynett.no> - 2014-06-16 10:41 +0200
                Re: SSD drive reliability. "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2014-06-17 10:24 +0000
                Re: SSD drive reliability. Måns Rullgård <mans@mansr.com> - 2014-06-17 12:24 +0100
                Re: SSD drive reliability. Richard Kettlewell <rjk@greenend.org.uk> - 2014-06-17 12:44 +0100
                Re: SSD drive reliability. David Brown <david.brown@hesbynett.no> - 2014-06-17 14:43 +0200
                Re: SSD drive reliability. "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2014-06-17 12:34 -0400
                Re: SSD drive reliability. David Brown <david.brown@hesbynett.no> - 2014-06-18 10:06 +0200
                Re: SSD drive reliability. "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2014-06-19 16:29 -0400
                Re: SSD drive reliability. Fredrik Jonson <fredrik@jonson.org> - 2014-08-13 09:15 +0000
                Re: SSD drive reliability. David Brown <david.brown@hesbynett.no> - 2014-08-13 13:09 +0200
                Re: SSD drive reliability. Richard Kettlewell <rjk@greenend.org.uk> - 2014-08-13 12:59 +0100
                Re: SSD drive reliability. David Brown <david.brown@hesbynett.no> - 2014-08-13 15:52 +0200
      Re: SSD drive reliability. JEDIDIAH <jedi@nomad.mishnet> - 2014-06-09 19:45 -0500
        Re: SSD drive reliability. David Brown <david.brown@hesbynett.no> - 2014-06-10 08:51 +0200
  Re: SSD drive reliability. "Vince Coen" <VBCoen@gmail.com> - 2014-06-10 11:49 +0100

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