User Manual

65
In addition, if your system contains four disk drives, it is possible to
use three drives to implement a RAID 5 data array with the fourth
drive kept as a spare disk. In this configuration, the system will
automatically use the spare disk to rebuild the array in the event of a
physical disk failure. A RAID 5 configuration can survive one disk
failure without losing any system functionality. When a disk fails in
RAID 5, the disk volume will operate in the "degraded mode". There is
no more data protection at this stage, and all the data will be lost if
the unit suffers a second disk failure. A failed disk should be replaced
immediately. Users can choose to install a new disk after turning off
the server or hot-swap the new disk while the server is running. The
status of the disk volume will change to "rebuilding" after installing a
new disk. Your disk volume will return to a normal status once the
volume rebuilding process is complete.
Note : To install a new disk when the server is running, first be sure
the disk volume is in the "degraded" mode. Or, wait to hear two long
beeps after the disk crash and then insert the new disk in place of
the failed disk.
RAID 6
The RAID 6 group is ideal for critical data protection needs. To
create a RAID 6 group, a minimum of 4 hard disks are required. The
total capacity of the RAID 6 group is equal to the size of the disk
with the smallest capacity in the array times the number of (hard
disks – 2). It is recommended (though not required) that only hard
drives of the same brand and capacity are used to establish the most
efficient hard drive capacity. RAID 6 can survive 2 disk failures and
the system can still operate properly.
Note : To install a new disk when the server is running, first be sure
the disk volume is in the "degraded" mode. Or, wait to hear two long
beeps after the disk crash and then insert the new disk in place of
the failed disk.