In case one DiskDomain has a storage pool wiht Raid5, lost two disk lost at a short time would make this diskdomian faulty.
This could be happened by some human swap errors.
All LUNs created from this diskdomain are fault.
1.insert the last lost disk back to same position.
the status of dsikdomain will be changed from faulty to degressed.
2.insert the previous lsot disk back to same position.
the status of diskdomain will be changed from degressed to normal.
V3 raid mechanism has its own data recovery principle. The system could recognize the old disks.
Please contact Huawei TAC to get the support if you don't know how to deal with such accident.