# /dev/mcelog is legacy on 4.12 kernel, mcelog vs rasdaemon?

## Tender

Hi,

just installed 4.12.5, mcelog says:

```

mcelog[3612]: Cannot open `/dev/mcelog': No such file or directory

```

difference between 4.9.34 and 4.12.5 .config:

```

midpower4 ~ # grep -i "mce" /root/config/linux-4.9.34

CONFIG_X86_MCE=y

CONFIG_X86_MCE_INTEL=y

CONFIG_X86_MCE_AMD=y

CONFIG_X86_MCE_THRESHOLD=y

CONFIG_X86_MCE_INJECT=m

CONFIG_EDAC_DECODE_MCE=m

# CONFIG_MCE_AMD_INJ is not set

midpower4 ~ # grep -i "mce" /usr/src/linux/.config

CONFIG_X86_MCE=y

# CONFIG_X86_MCELOG_LEGACY is not set

CONFIG_X86_MCE_INTEL=y

CONFIG_X86_MCE_AMD=y

CONFIG_X86_MCE_THRESHOLD=y

CONFIG_EDAC_DECODE_MCE=m

# CONFIG_MCE_AMD_INJ is not set

```

4.12 has introduced CONFIG_X86_MCELOG_LEGACY

https://cateee.net/lkddb/web-lkddb/X86_MCELOG_LEGACY.html

```

Enable support for /dev/mcelog which is needed by the old mcelog userspace logging daemon. 

Consider switching to the new generation rasdaemon solution.

```

I did not find rasdaemon in portage, is it the substitute for mcelog?

In the meantime, I will enable CONFIG_X86_MCELOG_LEGACY...

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## ct85711

Sadly, I don't know much about this rasdaemon, nor did I find much information about it.

The most I can find, is that it seems rasdaemon is more of mcelog remade with a few more capabilities.  Beyond that, it looks like you can find the rasdaemon package from the eva overlay.

https://gpo.zugaina.org/sys-apps/rasdaemon

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## mstockin

I found this presentation. It explains rasdaemon:

http://events.linuxfoundation.org/sites/events/files/slides/RAS_presentation_LinuxCon_NA_0.pdf

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## Goverp

Beware - necromancy:

I found this thread while reading up on MCE handling.  You might like to read  this topic

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