S2600GZ and S2600GL

Product Architecture Overview Intel® Server Board S2600GZ/GL TPS
An SFO Event is logged to the BMC SEL. The failing rank is then disabled, and any further Correctable Errors
on that now non-redundant channel will be disregarded.
The correctable error that triggered the SFO may be logged to the BMC SEL, if it was the first one to occur in
the system. That first correctable error event will be the only one logged for the system. However, since each
channel is a Sparing Domain, the correctable error counting continues for other channels which are still in a
redundant state. There can be as many SFO Events as there are memory channels with DIMMs installed.
3.2.4.5.6
Mirrored Channel Mode
Channel Mirroring Mode gives the best memory RAS capability by maintaining two copies of the data in main
memory. If there is an Uncorrectable ECC Error, the channel with the error is disabled and the system
continues with the “good” channel, but in a non-redundant configuration.
For Mirroring mode to be to be available as a RAS option, the DIMM population must be identical between
each pair of memory channels that participate. Not all channel pairs need to have memory installed, but for
each pair, the configuration must match. If the configuration is not matched up properly, the memory operating
mode falls back to Independent Channel Mode.
Mirroring Mode is enabled/disabled in the Memory RAS and Performance Configuration screen in the <F2>
BIOS Setup Utility.
When Mirroring Mode is operational, each channel in a pair is “mirrored” by the other channel. The impact on
Effective Memory size is to reduce by half the total amount of installed memory available for use.
When Mirroring Mode is operational, the system treats Correctable Errors the same way as it would in
Independent channel mode. There is a correctable error threshold. Correctable error counts accumulate by
rank, and the first event is logged.
What Mirroring primarily protects against is the possibility of an Uncorrectable ECC Error occurring with critical
data “in process”. Without Mirroring, the system would be expected to “Blue Screen” and halt, possibly with
serious impact to operations. But with Mirroring Mode in operation, an Uncorrectable ECC Error from one
channel becomes a Mirroring Fail Over (MFO) event instead, in which the IMC retrieves the correct data from
the “mirror image” channel and disables the failed channel. Since the ECC Error was corrected in the process
of the MFO Event, the ECC Error is demoted to a Correctable ECC Error. The channel pair becomes a single
non-redundant channel, but without impacting operations, and the Mirroring Fail Over Event is logged to SEL
to alert the user that there is memory hardware that has failed and needs to be replaced.
Revision 2.4
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