Hi, I remember seeing some discussion on what sector a partition starts on. Many programs create partitions that start on sector 63, which doesn't really make any intuitive sense to me. I just lost a disk from of a RAID10 array and was thinking I'd try to understand this issue as I have to do some disk/block/partition wrangling anyway. >From a discussion from linux-raid titled "Raid 10 LVM JFS Seeking performance help", I found the following: On Mon, Dec 21, 2009 at 12:56 PM, Goswin von Brederlow <goswin-v-b@xxxxxx> wrote: > > Also, on a lower level, make sure your raid does not start on a > partition starting at sector 63 (which is still the default in many > partitioning progs). That easily results in bad alignment causing 4k > chunks to land on 2 sectors. But you need to test that with your > specific drive to see if it really is a problem. > Hmm ... In short: Do I want to have a partition start on any particular sector? Especially in the case where I want to ... - build a RAID10 with partitions (i.e. not with raw devices) - using ~256K chunks - and have a nice JFS filesystem on top of it. Starting on sector 64 feels conceptually "prettier" than Sector 63, but I can't picture the case where it behaves any different. Except perhaps when GRUB expects stuff to begin at sector 63, making a mess if we're starting at sector 64. Though it *should* work OK, of course. Anyways ... Any tips on a subtle matter most well appreciated. Especially tell me if I'm overthinking, please. Thanks. -- Kristleifur -- 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
