APC iSCSI SATA II User Manual

 

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Sometimes, rebuild is called recover; these two have the same meaning. The following 
table is the relationship between RAID levels and rebuild. 
 
 

Disk striping. No protection for data. RG fails if any hard drive 

fails or unplugs. 

RAID 1 

Disk mirroring over 2 disks. RAID 1 allows one hard drive fails or 

unplugging. Need one new hard drive to insert to the system and 
rebuild to be completed.  

Extension to RAID 1 level. It has N copies of the disk. N-way 

mirror allows N-1 hard drives failure or unplugging. 

Striping with parity on the dedicated disk. RAID 3 allows one 

hard drive failure or unplugging. 

Striping with interspersed parity over the member disks. RAID 5 

allows one hard drive failure or unplugging. 

2-dimensional parity protection over the member disks. RAID 6 

allows two hard drives failure or unplugging. If it needs to rebuild 
two hard drives at the same time, it will rebuild the first one, 
then the other in sequence. 

Mirroring of RAID 0 volumes. RAID 0+1 allows two hard drive 
failures or unplugging, but at the same array. 

Striping over the member of RAID 1 volumes. RAID 10 allows 
two hard drive failure or unplugging, but in different arrays. 

The abbreviation of “Just a Bunch Of Disks”. No data protection. 
RG fails if any hard drive failures or unplugs.