Re: [libvirt] [PATCH 0/2] Add 'l2-cache-size' property to specify maximum size of the L2 table cache for qcow2 image
[Cc: Alberto Garcia of QEMU, who added the 'l2-cache-size' upstream]
On Wed, Nov 15, 2017 at 05:54:13AM -0500, John Ferlan wrote:
On 11/14/2017 08:58 PM, Lin Ma wrote:
> Lin Ma (2):
> caps: Add capability for maximum size of the qcow2 L2 table cache
> qemu: Add support for 'l2-cache-size' property of qcow2
>
There's already something on list about l2 cache, see
https://www.redhat.com/archives/libvir-list/2017-September/msg00553.html
it adds 3 related variables. IIRC, the "hold up" is how best to describe
how to use it or provide the feature in such a way that it's
"understandable" for general consumption without making a "policy"
that
generates certain values based on expected usage/needs for the client.
I recall Alberto saying that there's a default value of QCOW2
'l2-cache-size', but it is (intentionally?) low. And that the value
depends on the workload / use case: size of the image, the amount of I/O
you want to do, etc.
There's also an RFE for OpenStack Nova to expose this. (But I don't
know if it makes sense to expose it at that level, yet.)
[...]
--
/kashyap