View source for Irreversible mdadm failure recovery

= Situation analysis =

A RAID array member has 2 area: RAID array information (which may be lost if you are here), and the Data area. As long as the Data area is not erased, you can consider the member as useful for the following steps. If Data area is erased, it should be considered as missing for the following steps (and if the missing member is mandatory, don't quit this page before taking a look at the "Unlucky situations" section: may be some files can be recovered).

You are about to recover entire access to your filesystem as long as:
*Your array is redundant and you didn't lose/overwrite any member data area
*Your array isn't redundant but hopefully, you didn't lose/overwrite any member data area
*Your array is redundant, you have lost/overwritten one member data area, but hopefully there is still enough others members left to get your data back
*The data inside your members are arranged in one consistent and predictable way all over the array

If you aren't lucky, don't quit this page before taking a look at the "Unlucky situations" section: there's still several things to verify before aborting.