On Jan 30, 2013, at 3:02 AM, Hugo Mills <h...@carfax.org.uk> wrote: > > That would be the case with "single" mode, not with RAID-0. > > With RAID-0, you'd get data striped equally across all (in this > case, both) the devices, up to the size of the second-largest one, at > which point it'll stop allocating space.
This raises a question about the desirability/feasibility of changing this behavior. It's common to have odd sized disks. It's unfortunate that most of the life of a 'single' paring of disks, there is no performance improvement possible; and also unfortunate that in 'raid0' it doesn't fall back to 'single' behavior to fill up the remaining space, instead of ending allocation. md raid0 will work on odd sized block devices, and it will fill up all the space. Presumably it does this by allocating chunks round robbin, and the point where a block device is full, it just starts allocating more chunks to the device(s) that have space. This means there's a distinction in behavior between md's level 'raid10' and separately creating "a stripe of mirrors", i.e. first creating raid1 arrays, then striping them with raid0. Chris Murphy-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
