Good morning Neil, On 10/20/2015 09:35 PM, Neil Brown wrote: > Nothing dumb about that - you don't need a --backup option. > If you did, mdadm would have complained. > > You only need --backup when the size of the array is unchanged or > decreasing. > mdadm reads the first few stripes and stores them somewhere in each of > the spares. md (in the kernel) then reads those stripes again and > writes them out in the new configuration. It appears that one of the > writes failed, others might have succeeded. This may not have corrupted > anything (the first few blocks are in the same position for both the old > and new layout) but it might have done. > If you do want to look for the backup, it is around about the middle of > the device and has some metadata which contains the string > "md_backup_data-1". If you find that, you are close to getting the > backup data back. Hmmm. This feature has advanced beyond my last look at the code. I was under the impression the backup option was only optional when mdadm could move the data offset. Does this new algorithm apply to v0.90 metadata, a v3.2 kernel, and v3.2.5 mdadm? Phil -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
