On Wed, Jan 13, 2010 at 6:13 PM, Mike Mestnik <cheako@xxxxxxxx> wrote: > What should this value be? From what I gather it should be the length > of data stored on a single disk for each RAID level block. If that's > the case how is it that two given data blocks are calculated to be on > separate drives? It seams to me that the stripe-width is also > essential in this regard, but the man page does not reflect this. > > For example let's say that stride=1, then which of the following > blocks are not on the same drive as 1: 8 9 10? > The answer is dependent on the number data disks, like so. > Where x = n - 1 or n depending on the RAID type. > if x = 2 then 9 > if x = 3 then 8 and 10 > if x = 5 then 8 and 9 > Wait!! I got this all wrong, one would need all of x, n, and stride to successfully determine the disk used for a given stride. Seams to me mkfs is missing some parameters. What about [-g blocks-per-group]... http://tldp.org/HOWTO/Software-RAID-0.4x-HOWTO-8.html > There is no way to make this calculation with out knowing x, further > more calculating x based of of both stride and stripe-width is round > about... Why not simply ask for x, the number of data disks and have > stripe-width be the value that is calculated, as stride might not go > into stripe-width evenly leaving you with a headache. > > Did I locate a bug? > > Is there a better forum for this discussion? > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
