Mariusz wrote: >> Did you ask your vendor / manufacturer of the raid layer ? What did they >> say ? > no, i haven't asked yet, but i'm going to do it. Maybe i should use dd command (create image all logical disk to another disk) and add new 3rd disk, create raid 5 volume and after restore system from dd image? Most vendors have their own way of doing raid type convertions and will expect the metadata to move in specific ways, so depending on the hba, you really are better off backing up the data elsewhere, perhaps remove one of the raid-1 disks, create a raid5 in degraded mode move the data over, and add the older disk as hotspare. But then again, that depends on how the hba does these things. - KB