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

From: david
Date: Wed Aug 26 2009 - 07:30:48 EST


On Wed, 26 Aug 2009, Pavel Machek wrote:

On Tue 2009-08-25 23:32:47, Rik van Riel wrote:
Pavel Machek wrote:

So, would you be happy if ext3 fsck was always run on reboot (at
least for flash devices)?

For flash devices, MD Raid 5 and anything else that needs it; yes that
would make me happy ;-).

Sorry, but that just shows your naivete.

Metadata takes up such a small part of the disk that fscking
it and finding it to be OK is absolutely no guarantee that
the data on the filesystem has not been horribly mangled.

Personally, what I care about is my data.

The metadata is just a way to get to my data, while the data
is actually important.

Personally, I care about metadata consistency, and ext3 documentation
suggests that journal protects its integrity. Except that it does not
on broken storage devices, and you still need to run fsck there.

as the ext3 authors have stated many times over the years, you still need to run fsck periodicly anyway.

what the journal gives you is a reasonable chance of skipping it when the system crashes and you want to get it back up ASAP.

David Lang

How do you protect your data is another question, but ext3
documentation does not claim journal to protect them, so that's up to
the user I guess.
Pavel

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