On Mon, Sep 21, 2020 at 05:54:59PM +0800, Coly Li wrote: > I am not sure whether virtual bcache device's optimal request size can > be simply set like this. > > Most of time inherit backing device's optimal request size is fine, but > there are two exceptions, > - Read request hits on cache device > - User sets sequential_cuttoff as 0, all writing may go into cache > device firstly. > For the above two conditions, all I/Os goes into cache device, using > optimal request size of backing device might be improper. > > Just a guess, is it OK to set the optimal request size of the virtual > bcache device as the least common multiple of cache device's and backing > device's optimal request sizes ? Well, if the optimal I/O size is wrong, the read ahead size also is wrong. Can we just drop the setting? -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
