Re: Help test softupdates journaling (SUJ)

From: Alexander Motin <mav_at_FreeBSD.org>
Date: Sat, 09 Jan 2010 11:53:02 +0200
Hi.

Jeff Roberson wrote:
> I have been augmenting softupdates with a small journal that will be
> processed in lieu of fsck in the event of a crash.  I have written some
> about this project here: http://jeffr_tech.livejournal.com/

Sounds cool, but I have one question. Excuse my possible ignorance.

I was looking for BIO_FLUSH consumers and haven't found UFS there.
Unbacked write caching probably can make SoftUpdates unreliable, but it
is bearable while foreground fsck is used. As I understand, journaled
recovery is more dependent on data coherency, and so needs either
unbacked write caching to be disabled, or BIO_FLUSH to be used in
respective points by FS code. Am I right? So what's about BIO_FLUSH?

-- 
Alexander Motin
Received on Sat Jan 09 2010 - 08:53:09 UTC

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