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Chapter 4 Advanced operation
4.1 Rebuild
If one physical disk of the VG which sets to protected RAID level (e.g.: RAID 3 or
RAID 5) is FAILED or has been plugged out, the VG becomes degrade mode,
then the system will detect spare disk to
rebuild
the degrade VG to a complete
one. It will detect dedicated spare as rebuild disk first, then global spare.
In degrade mode, the status of VG will display
“DG”
.
When rebuilding, the status of PD/VG/UDV will display
“R”
; and
“R%”
in UDV
will display the ratio in percentage. After complete rebuilding,
“R”
and
“DG”
will
disappear. VG will become complete one.
Sometimes, rebuild is called recover; these two have the same meaning. The
following table is the relationship between RAID levels and rebuild.
RAID 0
Disk striping. No protection. VG will fail if any hard drive fails
or plugs out.
RAID 1
Disk mirroring over 2 disks. RAID 1 allows one hard drive fails
or plugs out. Need one new hard drive to insert and rebuild to
complete.
N-way
mirror
Extension to RAID 1 level. It has N copies of the disk. N-way
mirror allows N-1 hard drives fail or plug out.
Tips
The list box will disappear if there is no VG or only VG of RAID
0, JBOD. Because these RAID level cannot be set dedicated
spare disk.
Caution
The system will not rebuild when the physical disk plug out and
insert into the same slot because of protecting the data in new
inserted disk. The physical disk must be set to FREE and
SPARE disk, then the system will start to rebuild.
