R&S SpycerBox Cell Hardware Manual page 41

The system disk array for the system/metadata hard disks comprises
two disks (one disk per each hard disk tray see section "Hard Disk Tray"
on page 2-6). They are connected to the RAID controller that applies a
RAID 1 to the data, meaning that they are protected by a mirroring of
the data between two disks. If one of the hard disks fails, the missing
data can be restored with the mirrored information stored on the other
disk.
Second disk fail
If the second disk fails in the meantime, the data will be unrecov-
erable.
Replace a broken hard disk immediately.
The main storage of the R&S DVS system comprises up to 28 hard
disks (14 hard disks per each hard disk tray in a RAID array) in the
SpycerBox Cell. These are connected to the RAID controller that ap-
plies a RAID 5 to the data. With this, the data is striped across these
hard disks during write procedures. At the same time the information
necessary to rebuild a failed hard disk (parity information) is generated
and written across the disks as well. With the parity information writ-
ten, one storage hard disk per hard disk tray (RAID array) can fail and
your data will still be recoverable due to the information stored on the
other disks.
Second disk fail in the same RAID array
If a second disk within the same RAID array (hard disk tray) fails in
the meantime, the data will be unrecoverable.
Replace a broken hard disk immediately.
SpycerBox Cell | Hardware Guide | Version 1.0
Rohde & Schwarz DVS GmbH
Maintenance
 Hard Disk Maintenance
5-3