Messages in this thread | | | Date | Mon, 23 Jan 2006 20:32:17 +0100 | From | Matthias Andree <> | Subject | Re: soft update vs journaling? |
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On Mon, 23 Jan 2006, John Richard Moser wrote:
> The idea of Soft Update was to make sure that while you may lose > something, when you come back up the FS is in a safely usable state.
Soft Updates are *extremely* sensitive to reordered writes, and more likely to be reordered at the same time than streaming to a linear journal is. Don't even THINK of using softupdates without enforcing write order. ext3fs, particularly with data=ordered or data=journal, is much more forgiving in my experience. Not that I'd endorse dangerous use of file system, but the average user just doesn't know.
FreeBSD (stable@ Cc:d) has no notion of write barriers as of yet as it seems, wedging the SCSI bus in the middle of a write sequence causes major devastations with WCE=1, and took me two runs of fsck to repair (unfortunately I needed the (test) machine back up at once, so no time to snapshot the b0rked partition for later scrutiny), and found myself with two hundred files relocated to the lost+found office^Wdirectory.
Of course, it's the "Doctor, doctor, it always hurts my right eye if I'm drinking coffee" -- "well, remove the spoon from your mug before drinking then" (don't do that) category of "bug", but it hosts practical relevance...
-- Matthias Andree - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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