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SubjectRe: Sync semantics.
Hi!

> What should I expect from a "sync" system call?
>
> The manual says:
>
> sync() first commits inodes to buffers, and then buffers to disk.
>
> and then goes on to state:
>
> ... since version 1.3.20 Linux does actually wait.
>
> [for the buffers to be handed over to the drive]
>
> So how long can I expect a "sync" call to take?
>
> I would expect that all buffers that are dirty at the time of the
> "sync" call are written by the time that sync returns. I'm currently
> bombarding my fileserver with some 40-60Mbytes per second of data to
> be written (*). The fileserver has 8G of memory. So max 8000 Mb of

Are you sure? Hitting 40MB/sec is hard when it involves seeking...

You may want to lower dirty_ratio...
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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