Originally posted by: Wouter Liefting
Have you checked the state with diag?
If a device is OK but was simply missing when the system booted, an mkdev -l hdisk3, or perhaps a cfgmgr, should solve things. But if the disk or array has failed then you're going to have to restore a backup somehow.
BTW I don't think RAID 10 on two disks is possible. AFAIK it requires four disks.