Messages in this thread | | | From | John Bradford <> | Subject | Re: Are linux-fs's drive-fault-tolerant by concept? | Date | Mon, 21 Apr 2003 10:35:21 +0100 (BST) |
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> > > What is so bad about the simple way: the one who wants to write > > > (e.g. fs) and knows _where_ to write simply uses another newly > > > allocated block and dumps the old one on a blacklist. The blacklist > > > only for being able to count them (or get the sector-numbers) in > > > case you are interested. If you weren't you might as well mark them > > > allocated and that's it (which I would presume a _bad_ idea). If > > > there are no free blocks left, well, then the medium is full. And > > > that is just about the only cause for a write error then (if the > > > medium is writeable at all). > > > > Modern disks generally do this kind of thing themselves. By the time > ^^^^^^^^^^^^ > How many times does Stephan need to say it? 'Generally do' > is not enough, because it means 'sometimes they dont'.
OK, _ALL_ modern disks do.
Name an IDE or SCSI disk on sale today that doesn't retry on write failiure. Forget I said 'Generally do'.
> Most filesystems *are* designed with badblock lists and such, > it is possible to teach fs drivers to tolerate write errors > by adding affected blocks to the list and continuing (as opposed > to 'remounted ro, BOOM!'). As usual, this can only happen if someone > will step forward and code it. > > Do you think it would be a Wrong Thing to do?
Yes, I do.
It achieves nothing useful, and gives people a false sense of security.
We have moved on since the 1980s, and I believe that it is now up to the drive firmware, or the block device driver to do this, it has no place in a filesystem.
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