USB management

[Christoph Bier]

Derek Broughton schrieb am 21.10.2005 20:33:

> Christoph Bier wrote:
> 
>>Derek Broughton schrieb am 21.10.2005 17:25:
>>
>>>Christoph Bier wrote:
>>>
>>>>But `atime' shouldn't be set for flash drives. As `async' `noatime'
>>>>should be set.
>>>
>>>That's a matter of preference.
>>
>>Flash drives have a limited write lifetime. The amount differs from
>>10 000 to 100 000. Every time you write access time to a sector it
>>shortens the lifetime of this sector and thus of the flash drive.
>>With an mp3 player for more than 200 Euro and a 1GB xd card for my
>>digicam my preference focuses on lifetime :-).
>>
>>Do you really need access times on a flash drive especially under
>>those circumstances?
> 
> As I understand it, the kernel doesn't usually write to flash drives "very
> often" (the quotes are because I really don't know :-)), which is why you

Every time you read from a flash drive access time is written to it.
So it depends on how you use your flash drive. To be honest I think
that nowadays many GNU/Linux users aren't geeks anymore that know
what they do and so they may use a flash drive like they shouldn't
use it. And that's one reason why I like Ubuntu: Even those users
can use GNU/Linux now without any risk.

> can't just pull a USB stick out of the port and expect it to be consistent.  

That's right and that's why I always unmount flash drives manually
or use sync on the command line.

BTW: Even with Win you can't pull a USB stick out of the port at any
time.

> You're right that I don't need atime - in fact, I've _never_ needed atime on
> my own system - but it's still a matter of preference, and therefore not a
> bug (though it might qualify as wishlist).  I've fairly frequently seen
> posts on this and other lists asking how they can make flash drive writes
> synchronous, primarily so that they don't have to worry about the effects
> of removing a partially updated stick.

Those people should really be pointed to
http://readlist.com/lists/vger.kernel.org/linux-kernel/22/111748.html

Since Ubuntu aims to be a highly and sensible preconfigured
GNU/Linux distribution I think the default for flash drives should
be noatime. I guess that many users don't care about mount options
for their devices. They just plug and ... hmm ... play ;-). And
depending on how they use their flash drive, with option atime it
may be damaged earlier than necessary. Missing access time is not
that bad I think. And who really needs it in turn knows what he's
doing and should be able to adapt the options, IMO. But maybe you're
right and it's not a bug. Sometimes bug or feature is also a matter
of preference :-).

Thanks for sharing your thoughts.

Christoph
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