BCM94780 User Manual
01/13/04
Broadcom Corporation
Page 4 The Hardware Document 94780-UM100-R
Drive Health Status Light
There is one green Drive Health Status light for each disk. This light indicates any problems with the disk that
have been detected by the BroadNAS. If the BroadNAS detects a disk in the corresponding slot and the
BroadNAS considers the disk to be free from errors, the light is constantly on. If the BroadNAS believes that
there is a problem with the disk, but it is still at least partly functional, the light blinks. A blinking light should be
considered as an important warning that the disk should be replaced, even if it seems to be working. In addition
to other methods, the BroadNAS uses a technology called SMART (Self-Monitoring Analysis and Reporting
Technology) to keep tabs on the health of disks and try to detect when a disk is starting to have problems
before any data is lost.
Drive Activity Lights
There are Drive Activity lights on the lower part of the front panel, one for each disk slot. Each light is on only
while the corresponding disk is actually being written or read, so these lights tend to fluctuate depending on
how heavily the BroadNAS is being used.
Drive Eject Request Buttons
For each disk slot, there is also one Drive Eject Request button that supports hot-swapping of disks. That
means that if there is more than one disk in the system, one of the disks can be replaced without interrupting
the use of the other one. This allows seamless upgrades of disks containing data protected by TwinCopy
technology. When TwinCopy is not being used, the data on the disk ceases to be available when the disk is
removed, but other disks in the system continue to function and be available without interruption.
If a disk is to be removed while the BroadNAS is running, the Drive Eject Request button should be pressed
once to cause the software to cleanly shut down its accesses to the disk and then electrically disconnect the
disk. The software then extinguishes the drive locked status light. When this light turns off, it is safe to remove
the disk. After removing the old disk and putting in the new one, push the button a second time to inform the
BroadNAS that the new disk has been inserted and is ready to use. At that point, the software electrically re-
connects that disk slot and starts using the disk. The drive locked status light and drive health status light turn
back on if all goes well to indicate that the new disk is locked in place and in good health.
Drive Lock
The Drive Lock is the one final control that the BroadNAS has for each disk slot, which is a physical lock that
requires a physical key provided with the BroadNAS. Using this lock helps avoid accidental disk removals and
discourages those without the key from removing disks.
The sledsare acquired from third parties, and there are a number of variants of these sleds. The variants range
from plain, inexpensive sleds with no external controls or displays to sophisticated sleds with temperature
measurements, alarms, and detailed LCD displays.
Note: No technology can predict all failures and disks can fail without the BroadNAS having detected
the coming problem in some cases. BroadNAS, however, improves system reliability by detecting the
kinds of problems that occur most of the time.
Note: There are additional buttons and displays on the disk sleds themselves that are specific to the
sledsand not directlyconnected to the BroadNAS. For details,refer to the documentation provided with
each sled.
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