Wouldn't you be getting the same data twice? or would the kernel request the half the data from one disk & the other from the other disk? (file1-> chunk1@disk1 & chunk2@disk2, chunk3@disk1 & chunk3@disk2) On Tue, Nov 17, 2009 at 12:02 AM, Kasper Sandberg <postmaster@xxxxxxxxxxx> wrote: > > On Mon, 2009-11-16 at 08:08 -0800, Christopher Chen wrote: > > On Mon, Nov 16, 2009 at 6:29 AM, Kasper Sandberg <postmaster@xxxxxxxxxxx> wrote: > > > Hello. > > > > > > I've been wanting to create a raid10 array of two SSDs, and I am > > > currently considering the layout. > > > > > > As i understand it, near layout is similar to raid1, and will only > > > provide a speedup if theres 2 reads at the same time, not a single > > > sequential read. > > > > > > so the choice is really between far and offset. As i see it, the > > > difference is, that offset tries to reduce the seeking for writing > > > compared to far, but that if you dont consider the seeking penalty, > > > average sequential write speed across the entire array should be roughly > > > the same with offset and far, with offset perhaps being a tad more > > > "stable", is this a correct assumption? if it is, that would mean offset > > > provides a higher "garantueed" speed than far, but with a lower maximum > > > speed. > > > > Do you plan to have more than two devices in the array? Raid 10 isn't > no > > magic. If you don't have more than do devices, I suppose your seek > > time might be half for reads (and higher for writes), but you won't be > > able to do any striping. > > > > I'm a bit confused as to the number of people popping in recently > > wanting to run raid 10 on two disk "arrays". > to get the doubled singlestream sequential read performance.. > > > > cc > > > > -- > 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 -- Majed B. -- 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
