A RAID 10 is a combination of RAID levels 1 and 0, whereby multiple RAID 1 systems are combined with a RAID 0 setup. That’s why RAID 10 is also frequently referred to as “RAID 1 + 0”. RAID 10 always consists of at least four hard disks.
Following the basic principle of RAID 1, in a RAID 10, the files are mirrored too. That means, data is duplicated to at least two disks in order to guarantee redundancy. At the same time, data is striped which means that data blocks are broken down into individual stripes and stored on the disks in a RAID 10. Storage media within a subordinate RAID 1 group always have the same data status, which in turn differs from the data status of all other subordinate RAID 1 clusters. Each group manages separate parts of the information, but that’s of no consequence to applications accessing the system.