Texas Memory Systems RamSam-210 - Manual (Page 8)

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1.3 Power Requirements
The RamSan-210 requires 150 watts of power for a fully loaded system. The RamSan-
210 includes two power supplies. Only one power supply is needed to run the system.
The power supplies are auto-ranging (they will accept either 110 or 220 power).
Each power supply is connected to an internal battery. The batteries provide at least one
hour of operation after a power failure. The power supplies and the batteries are linked.
In other words, if a power supply is not plugged into the system, its attached battery will
not work. If the power supply is broken its attached battery will not work. If the power
supply is plugged in and functional, the battery should operate properly. In the event one
battery or power supply is disabled, the other functional power supply and battery
combination will be able to handle system operation. Power supply temperature can be
monitored from the system monitoring software.
If power is lost, the system will operate for a user-defined number of minutes before
shutting down. When the system shuts down it will clear the write buffers by writing to
the mirrored internal disk drives.
When power is restored, the RamSan-210 will resume normal operations after restoring
system memory with the data from the disk drives. The system will also begin
recharging the batteries. Battery charge levels can be monitored using the bundled
remote monitoring software.
1.4 Non-Volatility
By utilizing internal hard drives and batteries, the RamSan-210 combines the
performance of SDRAM storage with the non-volatile nature of hard disk drives. The
RamSan-210 is equipped with dual, redundant, hot-swappable hard drives. Each of these
drives is able to operate at about 30 MB/sec during operation. RAID-1 is implemented
on this drive array to provide a redundant configuration for the non-volatile storage. In
order to operate the drives after a power failure occurs, the RamSan-210 contains dual
redundant batteries. When fully functional and fully charged, the batteries are able to
provide about one hour of operation.
The management control port (MCP) monitors the internal disks and batteries for a
failure condition. In such an event, the management card will notify the operator of an
error through the front panel display and over the Ethernet.
The RamSan-210 operates in mirrored write mode. All data written to the RamSan-210
system memory is also automatically mirrored to the internal disk drives. An internal
cache is used to allow for write bursts to occur without incurring a delay for each write.
Since all write operations are synchronous in this mode, there is no need to copy data
from memory to disk when a power failure occurs. The system simply waits a user
selectable amount of time (default of 5 minutes) before the RamSan-210 is powered off.
While writes are made to both disks and memory, all reads are done directly from
memory. Therefore, the RamSan-210 is an excellent solution for applications that are