When a controller is shut down or otherwise rendered inactive—its Link Status LED remains illuminated—
falsely indicating that the controller can communicate with the host. Though a link exists between the host
and the chip on the controller, the controller is not communicating with the chip. To reset the LED, the
controller must be power-cycled (see
Cache Status LED details
If the LED is blinking evenly, a cache flush is in progress. When a controller module loses power and write
cache is dirty (contains data that has not been written to disk), the supercapacitor pack provides backup
power to flush (copy) data from write cache to CompactFlash memory. When cache flush is complete, the
cache transitions into self-refresh mode.
If the LED is blinking momentarily slowly, the cache is in a self-refresh mode. In self-refresh mode, if primary
power is restored before the backup power is depleted (3–30 minutes, depending on various factors), the
system boots, finds data preserved in cache, and writes it to disk. This means the system can be operational
within 30 seconds, and before the typical host I/O time-out of 60 seconds, at which point system failure
would cause host-application failure. If primary power is restored after the backup power is depleted, the
system boots and restores data to cache from CompactFlash, which can take about 90 seconds. The cache
flush and self-refresh mechanism is an important data protection feature; essentially four copies of user data
are preserved: one in controller cache and one in CompactFlash of each controller. The Cache Status LED
illuminates solid green during the boot-up process. This behavior indicates the cache is logging all POSTs,
which will be flushed to the CompactFlash the next time the controller shuts down.
CAUTION: If the Cache Status LED illuminates solid green—and you wish to shut-down the controller—do
so from the user interface, so unwritten data can be flushed to CompactFlash.
Power supply LEDs
Power redundancy is achieved through two independent load-sharing power supplies. In the event of a
power supply failure, or the failure of the power source, the storage system can operate continuously on a
single power supply. Greater redundancy can be achieved by connecting the power supplies to separate
circuits. Power supplies are used by controller and drive enclosures.
1 — Input Source Power Good
2 — Voltage/Fan Fault/Service
Powering on/powering off
Figure 45 LEDs: AC power supply unit — rear panel
on page 28
Power is on and input voltage is normal.
Power is off, or input voltage is below the minimum
Output voltage is out of range, or a fan is operating below
the minimum required RPM.
Output voltage is normal.
Lenovo Storage S3200/S2200 Setup Guide