Dulce Systems Duo-FireWire - Manual (Page 11)

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Duo-FireWire Installation and User’s Manual
6. Operating
6.1. DISK Activity Indicators
The DISK 1 and DISK2 Indicators show the activities of the two disk drives in the
Duo-FireWire. When the indicator is on it shows the particular drive is active.
DISK 1 and DISK 2 indicators do not always come on at the same time.
Depending on the Operating Mode selected, these indicators will act differently.
See the particular selected mode for more specific details.
6.1.1. RAID 0 - Stripe Mode (Performance)
The DISK1 and DISK2 indicators will be mostly active at the
same time. In the RAID 0 scheme data is alternately stored
between the two drives at a rapid rate. For example, when a
file is written to the Duo-FireWire, a small portion will be stored
on DISK 1, the next small portion on DISK 2, the next small
portion back on DISK 1. This process is called data striping.
This scheme provides the highest data rate that is the sum of
the two individual disk drives.
6.1.2. RAID 1 - Mirror Mode (Protection)
RAID 1 - During read operation
During read operating, one of the DISK
indicators will come on, either DISK 1 or
DISK 2. Since data on both drives are
identical, the internal controller will pick the
most efficient disk to use.
RAID 1 - During write operation
During write operation, both DISK 1 and DISK 2’s indicators
will come on. In Mirror Mode, data sent to the Duo-FireWire
will be written to both disk drives for redundancy. If one of the
DISK indicators do not come on during write operations, that
disk has failed and the unit will need servicing. Normal
operating continues on the remaining surviving disk drive.
RAID 1 - During write operation (with a failed disk drive)
A failed disk is indicated by the
absence of disk activities during
write operations. Should a disk
become inoperative (defective), the DISK
indicator of that drive will never come on. In
such a case, the unit will need servicing.
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Duo-FireWire Installation and User’s Manual
RAID 1 - No operation (DISKs blinks)
If there are no read or write activities to the Duo-FireWire and
both DISK 1 and DISK 2 indicators are blinking, this indicates
the Duo-FireWire is performing a Syncing operation. This is
where the Duo-FireWire has detected a Mirror Mode out of
sync condition and is in the process of updating the portion of
the disk drive that is out of sync.
During the Syncing operation, data access to the unit will be slow. It is best to
allow the unit to be dedicated fulltime to complete the Syncing. This process can
take a few minutes to a few hours.
6.1.3. SPAN - Linking Mode (Simplicity)
DISK 1 indicator comes on when accessing
data on the 1 st half of the Duo-FireWire
space. DISK 2 indicator will come on when
accessing on the 2 nd half of the Duo-
FireWire space.
6.1.4. JBOD - Just a Bunch of Disks Mode (Individual)
DISK 1 indicator comes on when disk 1 is
being accessed. DISK 2 indicator comes on
when disk 2 is being accessed. Each of the
two disk drives in the Duo-FireWire shows
up as two independent disk drives.