bad sector in gmirror HDD

perryh at perryh at
Sun Aug 21 02:13:19 UTC 2011

Jeremy Chadwick <freebsd at> wrote:

> ... using dd to find the bad LBAs is the only choice he has.

or sysutils/diskcheckd.  It uses a 64KB blocksize, falling back to
512 -- to identify the bad LBA(s) -- after getting a failure when
reading a large block, and IME it runs something like 10x faster
than dd with bs=64k.

It would be advisable to check syslog configuration before using
diskcheckd, since that is how it reports and there is reason to
suspect that the as-shipped syslog.conf may discard at least some
of diskcheckd's messages.

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