On Jan 8, 2013, at 12:59 AM, Ross Boylan <ross@xxxxxxxxxxxxxxxx> wrote: > > Using /dev/sdb > Model: ATA WDC WD2003FYYS-0 (scsi) > Disk /dev/sdb: 3907029168s > Sector size (logical/physical): 512B/512B > Partition Table: gpt > > Number Start End Size File system Name Flags > 1 34s 999999s 999966s extended boot loaders > 2 1000000s 2929687s 1929688s ext3 /boot boot > 3 2929688s 6835937s 3906250s swap > 4 6835938s 3907029134s 3900193197s main > > Using /dev/sdc > Model: ATA WDC WD2003FYYS-0 (scsi) > Disk /dev/sdc: 3907029168s > Sector size (logical/physical): 512B/512B > Partition Table: gpt > > Number Start End Size File system Name Flags > 1 34s 999999s 999966s extended boot loaders > 2 1000000s 2929687s 1929688s ext3 boot boot > 3 2929688s 6835937s 3906250s swap > 4 6835938s 3907029134s 3900193197s main > > BTW the spec sheet for the WDC "red" drives says they use advanced > formatting (I may not have the buzzword quite right) with physical > sectors of 4k. So the reported sector size is a fib. Yeah you're using an old version of parted for it to not recognize that the physical sectors are 4096 bytes. The thing is, that it's a 512e disk, so the LBA's are still 512 bytes. And by the looks of it, your partitions are not aligned on those 4K physical sectors because the start value is 34s. In any recent fdisk or parted or gdisk, the start sector is 2048 (1MiB), and each partition is aligned on 8-sector boundaries. So your disks aren't properly partitioned, and you're getting a performance hit because of it. What I'm not getting is why your md0, comprised of sda1 at 192717s, and sd[bc]2 are 1929688s. What am I missing here? Because those values aren't at all the same. It's a 10x difference. And then with md1, comprised of sda3 at 1461047490s, and sd[bc]4 are 3900193197s. A 2.66x difference. What is this? sda1 is 696GiB, while sd[bc]4 are 1.8TiB each? Ummm… Chris Murphy-- 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
