[ovirt-devel] VDSM changes Linux memory dirty ratios - why?

[Martin Polednik]

On 30/11/16 13:10 +0100, Sven Kieske wrote:
>On 30/11/16 08:48, Martin Polednik wrote:
>> It's not really irrelevant, the host still uses disk cache. Anyway,
>> there is BZ[1] with a presentation[2] that (imho reasonably) states:
>>
>> "Reduce dirty page limits in KVM host to allow
>> direct I/O writer VMs to compete successfully
>> with buffered writer processes for storage
>> access"
>>
>> I wonder why virtual-host tuned profile doesn't contain these values:
>>
>> $ grep vm.dirty /usr/lib/tuned/virtual-host/tuned.conf
>> vm.dirty_background_ratio = 5
>>
>> [1]https://bugzilla.redhat.com/show_bug.cgi?id=740887
>> [2]http://perf1.lab.bos.redhat.com/bengland/laptop/rhev/rhev-vm-rsptime.pdf
>
>Could you share [2] with the wider community? This would be awesome!

Sorry, I've totally missed the fact it's internal link (unfortunately
publicly visible on the BZ). I believe it's slightly outdated, but
let's ask the author.

Ben, is the document[2] somehow still valid and could it be made publicly
available?

Re-referencing for completeness:
[2]http://perf1.lab.bos.redhat.com/bengland/laptop/rhev/rhev-vm-rsptime.pdf

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>
>Sven Kieske
>
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