mirrored file systems

[Bob Goudreau]

In article <4882 at amelia.nas.nasa.gov> truesdel at sun217..nas.nasa.gov (David A. Truesdell) writes:
>In addition, a mirrored filesystem won't help your I/O throughput.

Actually, that depends on the system's read/write ratio.  Writes to
a mirrored file system obviously must result in I/O to each (valid)
side of the mirror.  But reads, on the other hand, only need to
find *one* good copy.  An intelligently implemented mirrored file
system can increase I/O throughput by distributing read requests
evenly among the copies, thus leaving the unused sides of the
mirror free to service other incoming read requests.

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