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SubjectJournaling pointless with today's hard disks?
In the German computer community, a statement from IBM[1] is
circulating which describes a rather peculiar behavior of certain IBM
IDE hard drivers (the DTLA series):

When the drive is powered down during a write operation, the sector
which was being written has got an incorrect checksum stored on disk.
So far, so good---but if the sector is read later, the drive returns a
*permanent*, *hard* error, which can only be removed by a low-level
format (IBM provides a tool for it). The drive does not automatically
map out such sectors.

IBM claims this isn't a firmware error, but thinks that this explains
the failures frequently observed with DTLA drivers (which might
reflect reality or not, I don't know, but that's not the point

Now my question: Obviously, journaling file systems do not work
correctly on drivers with such behavior. In contrast, a vital data
structure is frequently written to (the journal), so such file systems
*increase* the probability of complete failure (with a bad sector in
the journal, the file system is probably unusable; for non-journaling
file systems, only a part of the data becomes unavailable). Is the
DTLA hard disk behavior regarding aborted writes more common among
contemporary hard drives? Wouldn't this make journaling pretty

1. (German)

Florian Weimer Florian.Weimer@RUS.Uni-Stuttgart.DE
University of Stuttgart
RUS-CERT +49-711-685-5973/fax +49-711-685-5898
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