Some HDD like a Western Digital WD20EARS uses 4KB sectors rather than 512 byte sectors (it is called “Advanced Format”). As result, if your partitions are mis-aligned, a read-modify-write performance penalty incurred.
If you want to align your partition with 4KB HDD sectors, you should create partition which starts from sector dividable by 8 (Linux uses 512 bytes sector size, so 4096 bytes / 512 bytes = 8). So, very easy.
# parted /dev/sde (parted) unit s (parted) mkpart primary 2048 400TB (parted) mkpart primary 781250560 -1 (parted) quit
Output for aligned HDD:
# parted /dev/sde unit s print Model: ATA XXXXXXXXXX (scsi) Disk /dev/sde: XXXXXXXXXXX Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type 1 2048s 781250559s 781248512s primary 2 781250560s 1953525167s 1172274608s primary
Parted “–align optimal” option can be used too to select optimal align, but disk parameters should be detected correctly to use this option with 4KB sectors.
Links: http://en.wikipedia.org/wiki/Advanced_Format http://en.wikipedia.org/wiki/GNU_Parted