Not really mandatory but optional. >From bcache documentation: "In the event of a data IO error on the flash it will try to recover by reading from disk or invalidating cache entries. For unrecoverable errors (meta data or dirty data), caching is automatically disabled; if dirty data was present in the cache it first disables writeback caching and waits for all dirty data to be flushed." Fernando On 14/09/2017 11:40, Emmanuel Florac wrote: Le Thu, 14 Sep 2017 10:10:09 -0300 FERNANDO FREDIANI <fernando.frediani@xxxxxxx> écrivait: If the users reads a piece of data that is just writen to SSD (unlikely) it should first and in any condition be commited to the permanent storage and then read from there and cached in another area of the SSD. Writaback cache is very volatile and lasts only a few seconds while the data is not yet committed to permanent storage. In fact multiple device suport is not implemented yet, that's why I am asking it and comparing with other well technology as ZFS. However nothing in bcache prevents you from using for instance a RAID of SSDs as a cache device. Actually for write caching it's mandatory IMO. -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
