Bad Blocks... Should I RMA?

Lowell Gilbert freebsd-questions-local at
Mon Nov 16 01:24:09 UTC 2009

"Ronald F. Guilmette" <rfg at> writes:

> Nov 15 15:24:17 coredump kernel: ad4: FAILURE - READ_DMA status=51<READY,DSC,ERROR> error=40<UNCORRECTABLE> LBA=256230591

This is *not* necessarily a big deal, despite what your other response
told you.  Errors on reads do not mean that your drive's bad-sector
table is full; only errors on write indicate that.  If you can try
manufacturer's drive diagnostics, do that.  If you can't, then it's
harder to fix things up, but not impossible; write back if you
really can't use a low-level diag.

Lowell Gilbert, embedded/networking software engineer, Boston area

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