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> Patrol scrubbing is a RAS feature of only more expensive platforms. All of the ECC-capable platforms I've used (including my AMD-based desktop PCs) have supp

> Patrol scrubbing is a RAS feature of only more expensive platforms. All of the ECC-capable platforms I've used (including my AMD-based desktop PCs) have supported patrol scrubbing. What have you used that doesn't?

jeffbee 6y ago
My AM4 motherboard doesn't offer any options for scrubbing and its manual is vague about whether ECC errors will even be reported to the operating system. By contrast my HPE ProLiant DL360 has firmware settings for scrubbing and I know the event reporting works because I see it in the logs all the time.
- theevilsharpie 6y ago
  The operating system will explicitly tell you at runtime if ECC support is available. If this returns an affirmative value, then ECC is working. Support for patrol scrubbing is a bit more variable. It's supported in my ASRock motherboard (B450M Pro4). It was also supported in two previous ASUS motherboards (AMD AM2 and AM3 platforms, respectively), although they called it something else that I can't remember. As well, a lack of a setting for patrol scrubbing doesn't necessarily mean that it's unavailable; it could just be enabled but not user-configurable.
  - marcan_42 6y ago
    This is OS-configurable. Look for /sys/devices/system/edac/mc/mc*/sdram_scrub_rate on Linux. The motherboard doesn't really get a say on whether the OS can correctly use ECC support on AMD as far as I know. As long as the memory is correctly initialized in ECC mode, the OS should always be able to use its EDAC driver to interact with it.
    - theevilsharpie 6y ago
      > The motherboard doesn't really get a say on whether the OS can correctly use ECC support on AMD as far as I know. This isn't entirely true. The motherboard needs to physically support ECC (i.e., traces for a 72-bit memory bus need to be present) for it to work. ECC support can also be disabled within the BIOS firmware, either explicitly via a user-adjustable toggle, or by the motherboard vendor hard-coding the setting to disabled. In any case, if the OS reports ECC as working, then ECC is fully functional.
      - marcan_42 6y ago
        My point is that once RAM is initialized in ECC mode, then the OS will see it. The motherboard can't support ECC mode but then screw up EDAC. That's why I said "as long as the memory is correctly initialized in ECC mode". It's a binary thing. Either the motherboard supports ECC, or it doesn't. If it supports ECC then you can always tweak the scrubbing from the OS.
    - jtl999 6y ago
      Some people claim Gigabyte X570 motherboards in theory have the traces needed for UDIMM ECC, but the (hardcoded) BIOS settings cause the memory to not initialize in ECC mode.

jeffbee 6y ago

My AM4 motherboard doesn't offer any options for scrubbing and its manual is vague about whether ECC errors will even be reported to the operating system. By contrast my HPE ProLiant DL360 has firmware settings for scrubbing and I know the event reporting works because I see it in the logs all the time.

theevilsharpie 6y ago
The operating system will explicitly tell you at runtime if ECC support is available. If this returns an affirmative value, then ECC is working. Support for patrol scrubbing is a bit more variable. It's supported in my ASRock motherboard (B450M Pro4). It was also supported in two previous ASUS motherboards (AMD AM2 and AM3 platforms, respectively), although they called it something else that I can't remember. As well, a lack of a setting for patrol scrubbing doesn't necessarily mean that it's unavailable; it could just be enabled but not user-configurable.
- marcan_42 6y ago
  This is OS-configurable. Look for /sys/devices/system/edac/mc/mc*/sdram_scrub_rate on Linux. The motherboard doesn't really get a say on whether the OS can correctly use ECC support on AMD as far as I know. As long as the memory is correctly initialized in ECC mode, the OS should always be able to use its EDAC driver to interact with it.
  - theevilsharpie 6y ago
    > The motherboard doesn't really get a say on whether the OS can correctly use ECC support on AMD as far as I know. This isn't entirely true. The motherboard needs to physically support ECC (i.e., traces for a 72-bit memory bus need to be present) for it to work. ECC support can also be disabled within the BIOS firmware, either explicitly via a user-adjustable toggle, or by the motherboard vendor hard-coding the setting to disabled. In any case, if the OS reports ECC as working, then ECC is fully functional.
    - marcan_42 6y ago
      My point is that once RAM is initialized in ECC mode, then the OS will see it. The motherboard can't support ECC mode but then screw up EDAC. That's why I said "as long as the memory is correctly initialized in ECC mode". It's a binary thing. Either the motherboard supports ECC, or it doesn't. If it supports ECC then you can always tweak the scrubbing from the OS.
  - jtl999 6y ago
    Some people claim Gigabyte X570 motherboards in theory have the traces needed for UDIMM ECC, but the (hardcoded) BIOS settings cause the memory to not initialize in ECC mode.