bad sector in gmirror HDD

[Alex Samorukov]

You can run long self-test in smartmontools (-t long). Then you can get 
failed sector number from the smartmontools (-l selftest) and then you 
can use DD to write zero to the specific sector. Also i am highly 
recommending to setup smartd as daemon and to monitor number of 
relocated sectors. If they will grow again - then it is a good time to 
utilize this disk.
> [root at bast:~] # dd of=/dev/null if=/dev/ad2 bs=1m conv=noerror
> dd: /dev/ad2: Input/output error
> 2717+0 records in
> 2717+0 records out
> 2848980992 bytes transferred in 127.128503 secs (22410246 bytes/sec)
> dd: /dev/ad2: Input/output error
> 38170+1 records in
> 38170+1 records out
> 40025063424 bytes transferred in 1544.671423 secs (25911701 bytes/sec)
> [root at bast:~] #
>
> That seems to indicate two problems.  Are those the values I should be using
> with dd?
>