Release Notes
8 Memory Errors and Dell PowerEdge YX4X Server Memory RAS Features
operate with SDDC coverage. At this point, memory performance will be impacted as the memory
controller must do two reads for every read to the mapped out cache-lines.
FYI: ADDDC will only provide fault coverage for sequential DRAM failures over
time. Two parallel DRAM failures within the same memory access still result in a
service outage. Additionally, ADDDC only applies to correctable errors and only
helps to protect an uncorrectable error from occurring by reducing the chance that
correctable errors become uncorrectable.
Memory Patrol Scrub
Memory Patrol Scrub Feature Support Table
Platforms Supported
Intel Platforms:
(Xeon SP Families Only)
AMD Platforms:
(All EPYC Families)
DIMMs Supported
x4 DIMMs:
x8 DIMMs:
Memory Patrol Scrub is a Dell memory RAS feature designed to decrease the probability of a user
encountering a multi-bit error by removing the accumulation of soft errors in DRAM. This in turn
reduces the chance of encountering an uncorrectable error (depending on other RAS capabilities
enabled and where the multi-bit error occurs). Memory patrol scrub works by having the CPU memory
controller periodically scan through DRAM and correct any single-bit errors that it encounters.
Memory patrol scrubbing is enabled by default and configured to perform in the background every 24
hours. Memory patrol scrub can be disabled or set to run at an accelerated schedule (every four hours)
in the BIOS setup under the power management menu. Memory patrol scrub may have an impact on
system performance for some workloads while it is running.
FYI: Demand Scrub occurs when the memory controller encounters a correctable
error during a regular run-time read transaction and writes back corrected data.
The usefulness of Patrol Scrub is highlighted in scenarios where memory access
patterns are highly focused in some areas and thus the other areas are not getting
the benefits of Demand Scrub.
Memory Page Retire (MPR)
Memory Page Retire Feature Support Table
Platforms Supported
Intel Platforms:
(Xeon SP Families Only)
AMD Platforms:
(All EPYC Families)
DIMMs Supported
x4 DIMMs:
x8 DIMMs: