Re: Have ext3 on SanDisk CF but can't disable write-back caching as kernel instructs

From: Dan Harkless (usenet_at_harkless.org)
Date: 07/18/03 

Date: 17 Jul 2003 20:40:38 -0700

Trevor Barton <tmb@Xisotek.co.uk> wrote in message
news:<slrnbhd69a.a1n.tmb@sheep.isotek.co.uk>:
> > No. Because of the "sync and then lock out all tasks that write to
> > disk when we go onto capacitor power" behavior I described before, the
> > ext3 is just there as an added protective measure against corruption
> > (and to prevent time-consuming fscks at boot-time).
>
> Yes, as I said it's a trade-off. I thought that there was some
> uncertainty about the length of the capacitor power reserve being
> sometimes inadequate, or was that some other poster's speculation?

Yes, there is currently uncertainty about that. The hope is that
after doing some timing tests we'll find that under normal conditions
we always have enough capacitor time to do the sync(). There's still
a worry about _unusual_ conditions resulting in an abormally high
amount of data that needs to be sync()ed, though, which is why I'm
reluctant to give up on a journalled filesystem.

Multiple people have said that ext3 is unwise because it'll cause more
writes to the Flash, but again, unless it's an order of magnitude
more, I don't see how that would be an issue. 

--
Dan Harkless
usenet@harkless.org
http://harkless.org/dan/

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