-- MikeGore - 30 Jan 2012

Advanced Format Drives

4k sector size drives

Note many of the drive manufactures are created drives with 4k sector sizes. It is important that file system utilities correctly align partitions to this new size or speed reductions by as much as half can be expected


Alignment and performance testing

Linux Benchmark and Tools

  • Disk Benchmark Testing* /usr/bin/palimpsest
    • This tools gives a great graphical overview of the drive performance.
    • Testing shows that you can lose 50% of your drive performance OR WORSE if partitions are not aligned


Detecting Advanced format Drives

  • list_drives: list drives - identify advanced format drives - display physical size

  • parted -l
       parted -l
       Model: ATA WDC WD30EZRS-00J (scsi)
       Disk /dev/sde: 3001GB
       Sector size (logical/physical): 512B/4096B
       Partition Table: gpt
       Number  Start   End     Size    File system  Name  Flags
        1      17.4kB  3001GB  3001GB  ext4

  • fdisk -l
       Disk /dev/sde: 3000.6 GB, 3000592982016 bytes
       255 heads, 63 sectors/track, 364801 cylinders
       Units = cylinders of 16065 * 512 = 8225280 bytes
       Sector size (logical/physical): 512 bytes / 4096 bytes
       I/O size (minimum/optimal): 4096 bytes / 4096 bytes
       Disk identifier: 0x00000000

Specifying Partition Alignment
    * GParted Manual
    * Working with Partitions
    * Intermediate Partition Actions
    * Specifying Partition Details
          To specify the alignment of the partition, use the
          Round to cylinders check box.
                    To enable, select the Round to cylinders
                    check box.
                    To disable, deselect the Round to cylinders
                    check box.

            When enabled, Round to cylinders
            aligns partition boundaries on the cylinder boundaries
            for the disk device.  Enabled is the default setting.

            If you want to maintain compatibility with old operating systems,
            enable Round to cylinders.
            If you do not want the start of an existing partition to move,
            then disable Round to cylinders
            and do not change the free space preceding value.

10.04 Tools

  • original fdisk does not align partitions
    • Work around: fdisk -H 224 -S 56 /dev/sdX - replace X with the drive you want to partition
    • NOTE - If you use *fdisk -uc make sure you subtract 1 for the last sector ending the next partition - or it will start with a sector that is over by 1!*
  • original gparted - requires manual settings to fix

USB enclosures

  • USB enclosures can hide the real drive settings

Vendor Tools


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Unknown file formatext list_drives r1 manage 0.6 K 2012-01-31 - 16:40 MikeGore list drives - identify advanced format drives - display physical size
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Topic revision: r3 - 2012-02-01 - MikeGore
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