On Mon, Sep 17, 2001 at 07:23:16AM -0700, Bob Miller wrote:
>
>Jacob Meuser wrote:
>
>> ffs with softupdate is really fast and reliable, but not truly
>> journaling.
>
>Does ffs+softupdate require an fsck after a crash?
>
Yes; the fsck is less demanding than before, however. One problem i have
seen under ffs+softupdate is that some kinds of crash can leave you in
a Damn Peculiar state (lots of bogus zero-byte files created, lots of existing
files with time stamps in 2036, lots of files with wierd flags...).
>Not having to fsck is the defining feature of a journaling
>filesystem, IMHO.
Well, all you've really done is trade fsck for journal restore, which
is also time-consuming, but at least is more reliable than fsck.
One of the more interesting crash-recovery schemes i've seen is in
ErOS (http://www.eros-os.org), which periodically saves a known-good
snapshot of the running system, so that if you have a crash, instead
of rebooting from scratch, it just restores from the known-good state,
so e.g. your shell sessions pick up where you left off.
--
"If my son wants to be a pimp when he grows up, that's fine with me. I
hope he's a good one and enjoys it and doesn't get caught. I'll support
him in this. But if he wants to be a network administrator, he's out of
the house and not part of my family." Steve Wozniak, http://www.woz.org
