Hi, I have a 4TB HDD with 4k sectors:
Disk /dev/sdb: 976754642 sectors, 3.6 TiB Logical sector size: 4096 bytes I would like to set up a single partition using GPT. gdisk sets up the partition to start at sector 8 by default: Number Start (sector) End (sector) Size Code Name 1 8 976754636 3.6 TiB 8300 Linux filesystem gdisk then is fine with the alignment: No problems found. 2 free sectors (8.0 KiB) available in 1 segments, the largest of which is 2 (8.0 KiB) in size. However, parted says the partition is not aligned: # parted /dev/sdb align-check opt 1 1 not aligned According to this howto <http://rainbow.chard.org/2013/01/30/how-to-align-partitions-for-best-performance-using-parted/> the first partition should start at sector 65535 with my HDD's parameters: # cat /sys/block/sdb/queue/optimal_io_size 268431360 # cat /sys/block/sdb/queue/physical_block_size 4096 268431360 / 4096 = 65535 So I changed the start sector accordingly: Number Start (sector) End (sector) Size Code Name 1 65535 976733639 3.6 TiB 8300 Linux filesystem Now parted is fine with the alignment: # parted /dev/sdb align-check opt 1 1 aligned But gdisk complains: Caution: Partition 1 doesn't begin on a 8-sector boundary. This may result in degraded performance on some modern (2009 and later) hard disks. So I wonder which start sector I should choose for optimal alignment? Thanks, Thomas
