On Sat, Sep 10, 2016 at 4:18 PM, Thor Lancelot Simon <[email protected]> wrote: > On Fri, Sep 09, 2016 at 11:09:49PM +0200, Jose Luis Rodriguez Garcia wrote: >> B- It can use the buffer cache for avoid read/write cycles, and do >> only writes if the data to be read is in memory. > > I'd stay more focused on avoiding _copies_. Any sane implementation > must satisfy reads from the cache layer if the data are cached. I > would avoid confusing this layer with the page or buffer caches.
What are these _copies_ ? I don't understand it. >> E- It can be useful to use elevator algorithms for do the writes from >> buffer cache to raid. > > I definitely don't agree. If you do this, you'll end up with request > sorting at at least three layers! The only reason to sort requests > would be if you were going to coalesce them, and I would again urge > that you do that later. I was thinking in do synchronous writes, from the cache. But it seems better to do asynchronous writes instead, and let Raidframe/other layer to do the sort. It is inefficient to do the sort several times. Two questions: 1- Do Raidframe/ld/other drivers allow asynchronous writes? 2- What drivers/layers do the actual sort/elevator algorithm? Yes I was thinking in coalesce them. I don't think that it is incompatible with that other layer performs the sorting
