> > lost+found). Short of going to a journaling file system, are
> > there any
> > other methods that anyone can recommend? (And no, I don't
> > have control of
> > the hardware so I can't prevent an unexpected shutdown.)
>
> I think of two solutions that could help:
> - Mount your partition read only and install a ramdisk for logs etc.
> - use initrd to run linux completely in ram
>
I'm already using a couple of RAM disks for /tmp, /dev, /etc, and /var
just for this reason, plus /usr, /bin, /lib, and others are mounted on
a read-only disk partition. I still need a non-volatile storage media
for user-configurable information. A RAM disk for the user information
might be a good idea if I were to copy it's contents back to the non-
volatile storage media on a proper shutdown, while an improper shutdown
would only lose the latest changes.
> I made experiments with reiserfs because I've got the same
> problem here. But
> I learned that also a journaling fs may become corrupt when
> power fails (the
> same with ntfs and embedded nt.)
That's troubling. I thought that the whole motivation for a journaling
file system was to fix this kind of problem. Were you using the 2.2 or
2.4 kernel series for your testing?
> One suggestion to the cracks: what about a kind of 'write
> filter' as it is
> used with embedded nt? Read data come from the flash/hd and
> when tried to
> write a file, this file is stored in ram instead of the
> flash/hd. Subsequent
> reads to that file go to the ram-copy. This leaves the system
> always in the
> same state when powering up but enables to work on it as if there's a
> writable flash/hd available. No write accesses to flashs, therefore no
> corrupted fs when suddenly powered down. Capable of running a
> system from a
> read-only device (CDROM...). Beside, one doesn't need to hold
> the whole
> root-fs in ram as it is done with initrd.
Sounds like a good idea though it may require a larger memory footprint
than I can live with. Are you aware of any Linux projects alongs these
lines? You'd think that when a 512MB DIMM costs US$40 we wouldn't still
need to make these trade-offs.
David Christensen
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