User manual

When rebuilding, the status of PD/VG/UDV is “R”; and “R%” in UDV will display
the ratio in percentage. After complete rebuilding, “R” and “DG” will disappear.
Sometimes, rebuild is called recover. These two have the same meaning. The
table below lists the relationship between RAID levels and rebuild.
RAID 0
Disk striping. No protection of data . VG fails if any hard drive
fails or gets unplug.
RAID 1
Disk mirroring over 2 disks. RAID 1 allows one hard drive
failure or unplugging. Need one new hard drive to insert to the
system for rebuild to be completed.
N-way
mirror
Extension to RAID 1 level. It has N copies of the disk. N -way
mirror allows N-1 hard drive failures or unplugging.
RAID 3
Striping with parity on the dedicated disk. RAID 3 allows one
hard drive failure or unplugging.
RAID 5
Striping with interspersed parity over the member disks. RAID
5 allows one hard drive fail ure or unplugging.
RAID 6
2-dimensional parity protection over the member disks. RAID
6 allows two hard drive failure or unplugging. If it needs to
rebuild two hard drives at the same time, it will rebuild the first
one, then the other.
RAID 0+1
Mirroring of the members of the RAID 0 volumes. RAID 0+1
allows two hard drives to fail or gets unplugged, but they need
to be part of the same array.
RAID 10
Striping over the members of the RAID 1 volumes. RAID 10
allows two hard drives to fail or gets unplugged, but they need
to be part of different arrays.
T
ips
The list box doesn’t exist if there is no VG or only VG of RAID
0, JBOD. This is because user cannot set dedicated spare disk
for these RAID levels.