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REBUILD
In Mirror mode, if one of the HDDs fails and is replaced with a functional HDD,
the RAID System will automatically rebuild the target HDD (the new functional
HDD) with data from the source HDD (the remaining functional HDD) sector by
sector. After the rebuild is completed, data in both HDDs will be identical. The
use of two identical HDDs from the same manufacturer, having the same
capacity and RPM is highly recommended.
When the chipset is processing the Rebuild task, if data is accessed during
this period, the speed of data access is around 2 ~ 3 MB/sec; thus, access of the
HDD during a Rebuild is not recommended.
ONLINE REBUILD
In most cases, Rebuild refers to "Online Rebuild", meaning the rebuild is initiated
when the RAID System is connected to the host. When the Online Rebuild is
initiated, the RAID System cannot rebuild if it is not connected to the host.
For the USB 2.0 model, it can only support Online Rebuild.
REBUILD EXISTING DATA TO A BACKUP HDD
Due to the Rebuild behavior, the first HDD inserted into one of the HDD trays and
recognized by the RAID System becomes the source HDD. To rebuild existing
data from a source HDD to a backup HDD (target HDD), the source HDD must
first be inserted into one of the two drive bays. After the host detects the source
HDD (in 10 to 15 seconds), and the RAID System indicates the target HDD tray
is empty via the LED disk error light, the target HDD should then be inserted in
the other HDD tray. The RAID System will then recognize the target HDD, the
disk error LED will stop, and the rebuild process will begin automatically. These
actions ensure that the RAID System recognizes the correct source and target
HDDs and to prevent the source data from being overwritten.
The Rebuild Speed of the USB 2.0 Model is 100 GB per hour or 28.4 MB
per second, approximately.
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