[Techtalk] Need the command to automatically sync mirrored drive

Maria Blackmore mariab at cats.meow.at
Fri Aug 22 01:48:49 EST 2003

On Thu, 21 Aug 2003, Lucky Lady wrote:

> I can't remember the command to sync my mirrored drive. When I run the
> command cat /proc/mdstat md0 is not mirrored. md1 through md5 are
> mirrored. Rebooting does not work.


Syncing will usually happen by itself.  Personally, I think that what you
should be asking is "why aren't my mirrored drives mirrored any
more?".  At this point you will need to fix this problem :)

Did something happen to one of the devices in the mirror?  Does it say
[1/2] [U_] at the end of the status line for md0 now?

Anyway, the easiest way to convince your machine to bring the other drive
back into the mirroring is the "raidhotadd" command.  So, for example, if
you are mirroring /dev/hda1 and /dev/hdc1, but hdc1 has been thrown out of
the array for some reason, and you want to readd it, you would use
"raidhotadd /dev/md0 /dev/hdc1", and the next time you look at mdstat it
should give you the progress on rebuilding.

have fun


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