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Dec 06, 2018 at 07:48 PM

Anyone have problems with raw devices when sqm_cache_enable=share (new default)

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I had some problems with a new Linux based repserver (version 16.0 SP03 PL05) where it got weird low level OS errors accessing Linux raw devices (for the stable queue).

I think it's related to the new new memory_control=smart and sqm_cache_enable=share default settings (where "smart" means automatically/dynamically tune memory usage within repserver modules, and "share" has something to do with sharing sqm memory when "smart" memory control is turned on)

Turning sqm_cache_enable to "on" seemed to solve the problem.

I think the problem might have been that the repserver was treating raw devices like a buffered file. When the repserver issued a flush-the-buffer command (aka osync or dsync), Linux responds with an I/O error (in rsaiolinux, in my case)

SAP tech support hadn't heard of anyone else having problems like this. Has anyone else seen this problem?

Thanks
Ben