OD has no more alternates for remap -- should I worry?

[Joshua W. Burton]

I have a NeXTcube with the Canon MO drive at home, and I have one disk that
I commonly use as a hard-drive extender; that is to say, I have several
hundred links from, e.g., /LocalLibrary/Literature/More over to
/MoreDisk/Library/Literature, and so on for nearly every other directory
that has `low-priority' goodies that can live on the removable medium.
This gives me lovely transparent access to the extra quarter gig of files,
but of course it means that ol' /MoreDisk gets a lot of use.

For the last six months my drive has been slowly getting flaky, in the
canonical pattern described in the FAQ's. First a few ECC errors, then a
lot, and finally last week a spin-up/spin-down lockup. Figuring that slow
dust accumulation was the culprit (my fan blows the right way, and the room
isn't really very dusty, but in four years who knows what can accumulate?),
I shelled out for one of the head-cleaning gadgets from Bell Atlantic. This
is a little cartridge that mates with your OD slot and then cleans the lens
manually; it's part number S3901, and you can order it at (800)499-6398.

Anyway, after cleaning my drive unquestionably sounds happier, and I don't
seem to get any more long runs of error-correction glitches. However (and
here we come at last to my question) there have been a few messages in the
console since the cleaning of the following stripe:

od0a: write failed (no more alternates for remap!) block 157152 phys block 158992 (14086:0:0)
od0a: write failed (no more alternates for remap!) block 157152 phys block 158993 (14086:0:1)

What does this mean? Reads and writes seem to work just fine, so I don't
know how to interpret the `write failed' complaint. It sounds as though
there are a certain limited number of spare blocks available for remapping
logical blocks to in case bad spots develop on the disk, and I squandered
all of them in the pre-cleaning days when read errors were coming fast and
furious. Is this in fact what is going on? If so, and assuming that the
cleaning cured the fundamental problem, can I get my lost sectors back
without rebuilding the disk? I have a full backup, but restoring 213 MB of
data from one oppy to another with a single drive, even using dd and big
packets, is going to be like kicking dead whales down the beach. Is there
an easier way? What will happen if I just ignore the console errors?

Thanks in advance. Please reply by email; I'll summarize.

It is not enough to succeed. |=================================================
Others must fail. | Joshua Burton (401)435-6370 bur...@het.brown.edu
-- Gore Vidal |=================================================