Messages in this thread |  | | Subject | Journaling pointless with today's hard disks? | From | Florian Weimer <> | Date | 24 Nov 2001 14:03:11 +0100 |
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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 anyway).
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 pointless?
1. http://www.cooling-solutions.de/dtla-faq (German)
-- Florian Weimer Florian.Weimer@RUS.Uni-Stuttgart.DE University of Stuttgart http://cert.uni-stuttgart.de/ RUS-CERT +49-711-685-5973/fax +49-711-685-5898 - 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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