Messages in this thread | | | Date | Fri, 25 Oct 2013 05:18:42 -0400 | From | Theodore Ts'o <> | Subject | Re: Disabling in-memory write cache for x86-64 in Linux II |
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On Fri, Oct 25, 2013 at 08:30:53AM +0000, Artem S. Tashkinov wrote: > My feeling is that vm.dirty_ratio/vm.dirty_background_ratio should _not_ be > percentage based, 'cause for PCs/servers with a lot of memory (say 64GB or > more) this value becomes unrealistic (13GB) and I've already had some > unpleasant effects due to it.
What I think would make sense is to dynamically measure the speed of writeback, so that we can set these limits as a function of the device speed. It's already the case that the writeback limits don't make sense on a slow USB 2.0 storage stick; I suspect that for really huge RAID arrays or very fast flash devices, it doesn't make much sense either.
The problem is that if you have a system that has *both* a USB stick _and_ a fast flash/RAID storage array both needing writeback, this doesn't work well --- but what we have right now doesn't work all that well anyway.
- Ted
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