Re: [Qemu-devel] [RFC] Re-evaluating subcluster allocation for qcow2 images

[Denis Lunev <den@virtuozzo.com>]

[snip]
>> ===========================
>>
>> And I think that's all. As you can see I didn't want to go much into
>> the open technical questions (I think the on-disk format would be the
>> main one), the first goal should be to decide whether this is still an
>> interesting feature or not.
>>
>> So, any questions or comments will be much appreciated.
> It does like very interesting to me at least for small subcluster sizes.
>
> For the larger ones, I suspect that the Virtuozzo guys might be
> interested in performing more benchmarks to see whether it improves the
> fragmentation problems that they have talked about a lot. It might end
> up being interesting for these cases, too.
>
> Kevin
There is no difference in terms of data continuity if the space
under the whole cluster is allocated with fallocate() as noted
by Berto.

For large sizes I have posted different use case but with
slightly different constraints. Subcluster option could be
interesting in terms of random IO on big disks even after
the allocation.

But can we get a link to the repo with actual version of
patches.

Den