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I hit an scenario where the update of the atime field in a Lustre file system from several simultaneous nodes performing reads on a single file is causing a severe performance loss.

Is there any way to ask an arbitrary command not to update the atime without having to mount the FS with the noatime option? Other users in the system could rely on this field for their operations, so I don't want to do system wide changes, if possible.

I can add the O_NOATIME flag in my own compiled programs, but I need to use it in other tools like gzip.

Poshi
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  • Have you considered mounting the fs with `relatime`? This should be the default on a modern Linux system, but someone may have changed it or you may be running a very old kernel. This limits atime changes to the shorter of 24 hours or whenever the file is modified, which should solve your problem without breaking apps that need atime. – Michael Hampton Feb 25 '21 at 16:09
  • It was not any of the options considered, but it could probably work. At the end, it is like noatime: it depends on knowing if someone needs it and which resolution is enough. We are considering the possibility of intercepting the open call to add the O_NOATIME flag to any call. Tomorrow I will do my first test with this workaround, although I would prefer to have some standard tool rather than having to write my own. But nobody knows about any tool like this :-( – Poshi Feb 25 '21 at 21:46

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