I search my bookmarks to find the original source, which has some benchmark to compare sector 63 and 64 http://linuxconfig.org/linux-wd-ears-advanced-format 2011/7/21 Erwan Leroux <erwan.lerou@xxxxxxxxx>: > It's 64 because it's the lowest sector that is a multiple of 4kB. > sector 63 is the lowest possible > you can see the result of that choice, using sector 64, the > corresponding cylinder is 1, so the drive is well aligned^^ > sudo fdisk -l /dev/sda > > WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util > fdisk doesn > 't support GPT. Use GNU Parted. > > > Disk /dev/sda: 2000.4 GB, 2000398934016 bytes > 255 heads, 63 sectors/track, 243201 cylinders > Units = cylinders of 16065 * 512 = 8225280 bytes > Sector size (logical/physical): 512 bytes / 512 bytes > I/O size (minimum/optimal): 512 bytes / 512 bytes > Disk identifier: 0x00000000 > > Device Boot Start End Blocks Id System > /dev/sda1 1 243202 1953514552 fd Linux raid autodetect > > sudo fdisk -lu /dev/sda > > WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util > fdisk doesn > 't support GPT. Use GNU Parted. > > > Disk /dev/sda: 2000.4 GB, 2000398934016 bytes > 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors > Units = sectors of 1 * 512 = 512 bytes > Sector size (logical/physical): 512 bytes / 512 bytes > I/O size (minimum/optimal): 512 bytes / 512 bytes > Disk identifier: 0x00000000 > > Device Boot Start End Blocks Id System > /dev/sda1 64 3907029167 1953514552 fd Linux raid autodetect > > i think i found this setting on that page but not really sure > http://ubuntuforums.org/showpost.php?p=9134230 > > > 2011/7/21 Paweł Brodacki <pawel.brodacki@xxxxxxxxxxxxxx>: >> 2011/7/21 Erwan Leroux <erwan.lerou@xxxxxxxxx>: >>> following is how i configured advanced format drives for raid 5 >>> i created one partition on each disk >>> >>> fdisk -u /dev/sdX >>> # -u change the unit displayed by fdisk to sector instead of >>> cylinders, this way it's easier to configure >>> >>> # the table partition isn't really modifier until you send the w >>> command, so if you messed up use the q to quit and restart >>> >>> #delete first partition of the disk, repeat until you had cleared the disk >>> d >>> >>> # create a new partition >>> n >>> >>> # select primary parition >>> p >>> >>> #select number one (don't know if number is important, i guess it's >>> means /dev/sdX1) >>> 1 >>> >>> #select first sector, here is the catch, to properly align the disk, select 64 >>> 64 >>> >> Why do you choose 64? One physical sector (4KiB) is 8 logical sectors >> (512 B). Would any number greater or equal to 8 and evenly divisible >> by 8 work as well? Are you aiming to align partition start with RAID >> chunk boundaries? >> >> Just curious. >> >> Paweł >> -- >> 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 >> > -- 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
