Re: [Qemu-block] [PATCH v7 6/9] qcow2: Increase the default upper limit on the L2 cache size

[Leonid Bloch]

> I don't actually think it's so bad to keep the cache permanently
> allocated, but I wouldn't object to a lower default for non-Linux hosts
> either. 1 MB may still be a little too low, 4 MB (covers up to 32 GB)
> might be more adequate. My typical desktop VMs are larger than 8 GB, but
> smaller than 32 GB.
>
> Kevin

And for a Windows VM just the OS installation takes above 40 GB. While 
we probably are not running Windows VMs for our own needs, it is very 
common that a customer of, for example, some cloud service uses QEMU 
(unknowingly) for a full-blown Windows. So 100 GB+ images which are 
quite heavily used is not a rare scenario. 256 GB - yeah, that would be 
on the higher end.

So 16 MB would indeed be a reasonable default for the *max.* L2 cache 
now, although below that would be too little, I think. 32 MB - if we 
want some future-proofing.

Leonid.