I see in the code setCacheMode for KVM is there - i'm not certain how to
invoke it to use writeback.
https://git-wip-us.apache.org/repos/asf?p=cloudstack.git&a=search&h=HEAD&st=grep&s=setCacheMode
On 6/6/16 7:26 AM, Vladimir Melnik wrote:
> Dear colleagues,
>
> I've found why guest's storage performance was much less than host's performance (the
mistake was too stupid to tell about it, really).
>
> But I'd like to ask one more question if you don't mind. :) I played with various KVM
options (cache, io and so on...) and now I can say that I got most IOpS with cache=writeback.
Tests are being performed with the fio utility, here is the jobfile contents:
> [readtest]
> blocksize=4k
> filename=/dev/vdb
> rw=randread
> direct=1
> buffered=0
> ioengine=libaio
> iodepth=32
> size=20%
>
> [writetest]
> blocksize=4k
> filename=/dev/vdb
> rw=randwrite
> direct=1
> buffered=0
> ioengine=libaio
> iodepth=32
> size=20%
>
> Is there any way to make ACS run create KVM domains with cache=writeback instead of cache=none
without patching the source code?
>
> Thank you!
>
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