gmirror slice insertion, "FAILURE - READ_DMA status=51<READY, DSC, ERROR>"

[Wojciech Puchar]

> so good. Began Ralf's procedure for inserting ad4s1 into mirror/gm0. The 
> synchronization began and reached 6% when this little horror appeared:
>
> ad6: FAILURE - READ_DMA status=51<READY,DSC,ERROR> error=40<UNCORRECTABLE> 
> LBA=134802751
> GEOM_MIRROR: Request failed (error=5). ad6s1[READ(offset=69018976256, 
> length=131072)]
> GEOM_MIRROR: Synchronization request failed (error=5). 
> mirror/gm0[READ(offset=69018976256, length=131072)]
>

your disk failed. (uncorrectable error)

assuming you eliminated other causes like drives overheating, cabling 
problem (don't think so) etc.:


boot from some kind of live CD, then make another mirror (single disk now) 
on other drive, then do

dd if=/dev/ad6s1 of=/dev/mirror/newmirror bs=2k conv=noerror,sync

i intentionally did bs=2k instead of larger, to minimize amount of lost 
data.

then change your system to boot from newmirror, take out /dev/ad6 and have 
it replaced on warranty (or buy new), put new ad6, insert it to the 
mirror.