Re: [patch] ext2/3: document conditions when reliable operation is possible

From: Rob Landley
Date: Wed Aug 26 2009 - 23:35:28 EST


On Monday 24 August 2009 19:08:42 Theodore Tso wrote:
> And if your
> claim is that several hundred lines of fsck output detailing the
> filesystem's destruction somehow makes things all better, I suspect
> most users would disagree with you.

Suppose a small office makes nightly backups to an offsite server via rsync. If
a thunderstorm goes by causing their system to reboot twice in a 15 minute
period, would they rather notice the filesystem corruption immediately upon
reboot, or notice after the next rsync?

> In any case, depending on where the flash was writing at the time of
> the unplug, the data corruption could be silent anyway.

Yup. Hopefully btrfs will cope less badly? They keep talking about
checksumming extents...

> Maybe this came as a surprise to you, but anyone who has used a
> compact flash in a digital camera knows that you ***have*** to wait
> until the led has gone out before trying to eject the flash card.

I doubt the cupholder crowd is going to stop treating USB sticks as magical
any time soon, but I also wonder how many of them even remember Linux _exists_
anymore.

> I
> remember seeing all sorts of horror stories from professional
> photographers about how they lost an important wedding's day worth of
> pictures with the attendant commercial loss, on various digital
> photography forums. It tends to be the sort of mistake that digital
> photographers only make once.

Professionals have horror stories about this issue, therefore documenting it
is _less_ important?

Ok...

Rob
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
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