An Exadata quarter rack has two database servers and three storage cells. In a typical setup, such a system would have three ASM disk groups, say DATA, RECO and DBFS_DG. Usually the disk group DATA would be high redundancy and the other two disk groups would be normal redundancy. The high redundancy disk group guards against the simultaneous failure of two partner disks or the complete failure of two storage cells.
There is a high (more...)