On Thu, Oct 04, 2012 at 03:54:06PM +0530, Kingsly John wrote: > Hi! > > I've been trying out bcache over the last couple of weeks and couldn't find > this explained anywhere. > > On my setup here while writing with cache_mode set to none, there's a > near constant 30-40kb/sec write happening to the flash device all through. > But in the other modes the amount of data written is significantly > higher.(While copying the same set of files into a freshly formatted bcache > device) > > Does setting cache_mode to none just disable the cache for reading or does it > disable it for both reading and writing? > > If it's only disabled for reads, then with cache_mode set to none would > bcache still recover from an unclean shutdown?
In cache_mode none, nothing new will be added to the cache (neither from writes nor cache misses), but the cache is still kept consistent - that's the reason for the writing that still happens to the flash devices, it's invalidating the cache whenever you do a write. It will still read from the cache, because there might still be dirty data in the cache. -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
