Re: mmap support with a dfuse-mounted posix conntainer

Faccini, Bruno

Ok, I can reproduce the behaviour you have reported.


Having a look to the related source code, this may come from the fact if caching is disabled, DFuse automatically/silently switches to direct-io mode, but then we may trigger the current Fuse Kernel module limitation that cause shared mmap() mappings to be  unsupported (ENODEV).



From: <> on behalf of "shmatsuu@..." <shmatsuu@...>
Reply to: "" <>
Date: Tuesday 31 May 2022 at 13:57
To: "" <>
Subject: Re: [daos] mmap support with a dfuse-mounted posix conntainer


Hi Bruno,

Thank you very much for checking! I'm using DAOS v2.0.1.One thing I forgot to mention previously is that I mounted the POSIX container with dfuse "--disable-caching" and got an error from mmap. Yes, without "--disable-caching" option, mmap succeeds with no errors in my environment as well. If you try to do dfuse mount with --disable-caching option, in your environment, does mmap succeed? I wanted to know if this is an expected behavior and to evaluate the effectiveness of caching in dfuse.

Thank you very much for your help,

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