Maintenance
Hard Disk Maintenance
5-2
SpycerBox Ultra/Flex | Hardware Guide | Version 3.1
Rohde & Schwarz DVS GmbH
5.1 Hard
Disk
Maintenance
This section deals with the possible event of a hard disk failure. First,
some introductory information about RAID are provided. After that fol-
low descriptions how to act when a hard disk fails.
5.1.1 Introduction to RAID
In a system where huge amounts of data are processed, large storage
capacities combined with high data throughputs are mandatory. To
provide both at the same time it is common practice in the area of video
and digital film to configure several hard disks together into a stripe set
or RAID. The IT world has defined several ’levels’ of RAID, most of them
providing some kind of data protection.
The RAID feature makes the R&S DVS system tolerant of disk failures.
Even with a broken disk operations can still be continued and, once the
failed disk has been replaced, the missing data can be recovered easily.
The data protection is provided by RAID controllers installed inside the
system. Each controller independently administers the data protection
for the set of hard disks that is connected to it.
The system disk array for the system/metadata hard disks comprises
four disks. They are connected to a 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.
The main storage of the R&S DVS system comprises up to 24 hard
disks in the SpycerBox Ultra and 48 hard disks in the SpycerBox Flex.
These are connected to three RAID controllers which connect a set of
eight hard disks each (SpycerBox Ultra; SpycerBox Flex: 16) and apply
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 nec-
essary to rebuild a failed hard disk (parity information) is generated and
written across the disks as well. With the parity information written,
one hard disk per disk set (RAID pack) can fail and your data will still be
recoverable due to the information stored on the other disks.
Data loss
If the second disk fails in the meantime, the data will be unrecov-
erable.
Replace a broken hard disk immediately.
