xRAID disks....

DA Forsyth iwrtech at iwr.ru.ac.za
Thu Jun 12 08:22:28 UTC 2008

On 12 Jun 2008 , DA Forsyth entreated about
 "Re: xRAID disks....":

> hmmm, thinking now the gmirror create/remove route will probably 
> work.  let me try it on a blankish disk and see....

this appears to be the answer to the question:
how to stop ar recognizing a disk that used to be on a raid 

doing a 'gmirror label gm0 /dev/ad1' filled the last sector with 
data, and 'gmirror clear /dev/ad1' reset it all to zero

now to try it on the big disk with data on it...
YES: it works, and the data slice is still there, and the commands 
happen a lot faster than a dd with a skip parameter

sidenote:  to see the last sector use sysinstall's fdisk to see the 
data for the disk.  you'll see something like

Disk name:      ad3                                    FDISK 
Geometry:  38913 cyls/255 heads/63 sectors = 625137345 sectors 
Offset       Size(ST)        End     Name  PType       Desc  Subtype  
         0         63         62        -     12     unused        0
        63  625137282  625137344    ad3s1      8    freebsd      165
 625137345       5103  625142447        -     12     unused        0
you want that number in a dd commmand like this
   dd if=/dev/ad3 skip=625142447 | hd -v			

Thanks to all for the pointers

       DA Fo rsyth            Network Supervisor
Principal Technical Officer -- Institute for Water Research

More information about the freebsd-questions mailing list