15 drives and 64K chunks gives 960K per stripe. The raid0 code should set the read-ahead to twice that: 1920K which I would have thought would be enough, but apparently not.
choosing the RA size should depend in some way on speed, shouldn't it? after all, the goal is to have enough reads queued to avoid a "stall" while un-read-ahead-ed sectors pass under the head. for a typical 60 MB/s, 7200 rpm disk, a track is .5 MB. the heuristic above only reads ahead .12 MB... regards, mark hahn. - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
