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Re: Lost file-system story

On Sun, Dec 11, 2011 at 05:04:23PM +0100, Joerg Sonnenberger wrote:
 > > I repeated the test without the sync, but waited 15 minutes after
 > > creating the new file before killing the power. When the system came
 > > up, I got fsck errors that were fixed, and the new file I created 15
 > > minutes before pulling the plug was not present. Whether this is
 > > intentional or a bug, I agree with David Holland -- it's wrong and
 > > should be fixed.
 > I disagree. It is exactly why I use FFS with -o async -- to get a disk
 > backed storage, that doesn't waste resources, if everything fits into
 > memory, but falls gracefully otherwise.

That's as may be, but it's still wrong. The syncer should be writing
out the metadata buffers as well as file data. (For your purpose,
you'd want it to be writing out neither, btw.)

Note the result from OpenBSD; we probably broke it with the UBC merge
and never noticed.

Don't we have at least one filesystem that doesn't support UBC? What
happens to it?

David A. Holland

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