On 09/20/2010 10:08 AM, Kevin Wolf wrote:
If you're comfortable with a writeback cache for metadata, then you
should also be comfortable with a writeback cache for data in which
case, cache=writeback is the answer.
Well, there is a difference: We don't pollute the host page cache with
guest data and we don't get a virtual "disk cache" as big as the host
RAM, but only a very limited queue of metadata.
Would it be a mortal sin to open the file twice and have a cache=none
version for data and cache=writeback for metadata?
The two definitely aren't consistent with each other but I think the
whole point here is that we don't care.
It opens up some other possibilities too like cache=none for data and
cache=writethrough for metadata which may be a useful combination.
Regards,
Anthony Liguori
