Not really familiar with Intel's "Mirrored Channel Mode" for a Blade Server setup (your typical moderately-heavy MySQL OLTP database running on the bare metal blade; no virtualization right now).
From the Intel docs I was able to find:
The Intel Xeon Processor 5500 series and Intel Xeon Processor 5600 series support channel mirroring to configure available channels of DDR3 DIMMs in the mirrored configuration. The mirrored configuration is a redundant image of the memory, and can continue to operate despite the presence of sporadic uncorrectable errors. Channel mirroring is a RAS feature in which two identical images of memory data are maintained, thus providing maximum redundancy.
On the Intel Xeon Processor 5500 series and Intel Xeon Processor 5600 series processors based Intel server boards, mirroring is achieved across channels. Active channels hold the primary image and the other channels hold the secondary image of the system memory. The integrated memory controller in the Intel Xeon Processor 5500 series and Intel Xeon Processor 5600 series processors alternates between both channels for read transactions. Write transactions are issued to both channels under normal circumstances.
However, I'm not really pickin' up what they're layin' down here. I lose half my storage capacity, but I gain "redundancy" of memory and possible gain read/write performance benefits? Like RAID 1 for RAM? Anybody have any practical experience with this configuration?