On 02/17/2017 05:03 AM, Reindl Harald wrote: >> Be careful. Don't confuse Raid10 with Raid1+0. They are NOT the >> same thing (on linux at least), although they are very similar > > yeah, i realized that but anyways thought the "writemostly" logic is > there too and maybe the docs not up-to-date Linux MD raid10 doesn't have a requirement that the number of devices be a multiple of the number of data copies. Which creates "interesting" data layouts with odd numbers of devices or similar effects with ,n3 or ,f3 layouts. Which makes it difficult if not impossible to designate specific devices as write mostly without weird operational asymmetries across the assembled array. In other words, it is not at all like raid 1 on top of raid 0, except in certain very limited cases, and your assumptions are simply wrong. If there are features (other than layouts) of raid10 that make you prefer it to raid1, it would make sense to ask for those features to be implemented in raid1. > sadly i can't write a patch on my own but only point how useful it > would be That's unfortunate. Patches are generally welcome. Phil -- 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
