User`s guide

StorTrends® NAS Software (Version 2.2) User’s Guide
118
RAID 0
RAID 0 provides disk striping across all hard disk drives in the volume. RAID 0 does not
provide any data redundancy, but does offer the best performance of any RAID level.
RAID 0 breaks up data into smaller blocks and then writes a block to each hard disk drive
in the volume. The size of each block is determined by the stripe size parameter, set
during the creation of the RAID set. RAID 0 offers high bandwidth.
By breaking up a large file into smaller blocks, StorTrends NAS Software can use
multiple IDE/SCSI channels and hard disk drives to read or write to the file faster. RAID
0 involves no parity calculations to complicate the write operation. This makes RAID 0
ideal for applications that require high bandwidth but do not require fault tolerance.
RAID 1
RAID 1 duplicates all data from one hard disk drive to a second hard disk drive. RAID 1
provides complete data redundancy, but at the cost of doubling the required data storage
capacity.
RAID 5
RAID 5 includes disk striping at the byte level and parity. In RAID 5, the parity
information is written to several hard disk drives. RAID 5 is best suited for networks that
perform a lot of small I/O transactions simultaneously.
RAID 5 addresses the bottleneck issue for random I/O operations. Since each hard disk
drive contains both data and parity numerous writes can take place concurrently. In
addition, robust caching algorithms and hardware based exclusive-or assist make RAID 5
performance exceptional in many different environments.
RAID Level
A RAID level in the StorTrends NAS Software can be either RAID 0, RAID 1, or RAID
5.
Mirrored OS
AMI has added Mirrored operating system (OS) capabilities to the StorTrends NAS
software in the 2.1 version release. Mirroring the NAS OS is the ability to install the NAS
software on two hard disk drives. Basically, if one of the two boot hard disk drives fail,
you still maintain the ability to boot to the NAS OS from the alternate hard disk drive.
Router
A device or, in some cases, software in a computer, that is connected to at least two
networks and decides which way to send each information packet based on its current
understanding of the state of the networks it is connected to.