Page 1 of 3 123 LastLast
Results 1 to 10 of 25

Thread: Partition 1 does not start on physical sector boundary.

  1. #1
    Join Date
    Jan 2006
    Beans
    302

    Partition 1 does not start on physical sector boundary.

    I'm trying to prepare 3 disks for a RAID5, but I get the above when trying to create the partition on two of the disks - the other one is fine.

    sdc does not produce the error, but sd[de] produce the error. See below for fdisk -l output. I previously had them in an array as whole disks, but I screwed it up so now I need to restore from backup, but I want to create the new array 'correctly'.

    I read an FAQ that said that I need to upgrade to a newer fdisk, but where can I get it from?

    Thanks,

    Max.

    11.04.

    Code:
    root@jeeves:~# fdisk -l /dev/sd[cde]
    
    Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes
    255 heads, 63 sectors/track, 121601 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: 0x00098452
    
       Device Boot      Start         End      Blocks   Id  System
    
    Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes
    255 heads, 63 sectors/track, 121601 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: 0x000ca99c
    
       Device Boot      Start         End      Blocks   Id  System
    
    Disk /dev/sde: 1000.2 GB, 1000204886016 bytes
    255 heads, 63 sectors/track, 121601 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: 0x00028409
    
       Device Boot      Start         End      Blocks   Id  System
    root@jeeves:~#

  2. #2
    Join Date
    Jan 2006
    Beans
    302

    Re: Partition 1 does not start on physical sector boundary.

    No one knows how to fix this issue? Perhaps someone has a recommendation for where best to ask?

  3. #3
    Join Date
    Oct 2009
    Beans
    2,199
    Distro
    Ubuntu 10.10 Maverick Meerkat

    Re: Partition 1 does not start on physical sector boundary.

    Hey hows it going? Tumbleweed blowing through the thread?
    Do you want to erase all 3 disks and reformat them from scratch...you have everything backed up, right?

    I'd suggest

    Code:
    sudo dd if=/dev/zero of=/dev/sdx bs=1M count=100 conv=notrunc,noerror
    repeat for each drive

    Use Disk Utility to "format drive" and give each one a new MBR.
    Then "File", "Create" and have it make a RAID 5 for you:
    512 stripe size
    Give it a name (but do not use spaces or it screws up the mdadm.conf!)
    Select the 3 drives
    Then where the array size slider is, at the right is a box with the size. Round it down to the nearest 0.1GB by editing the number. Eg: If it says 2000.123GB then change it to 2000.1GB.
    Then set it going.

    It will give it an arbitrary device name that is not being used, /dev/mdN
    Click on the RAID device icon on the left and then the partition in the graphic and then "Format Volume".

    Finally, add the ARRAY directive to mdadm.conf.
    Code:
    sudo mdadm -Ds
    copy the line for the new RAID to mdadm.conf and change the device name to /dev/md? as you wish.
    Delete or comment out the old RAID5 one.

    Stop the array and reassemble it to make sure mdadm.conf is right
    Code:
    mdadm --stop /dev/mdN  (its current name)
    Code:
    mdadm -As
    check it reports assembling it with the device name you specified in mdadm.conf

    edit fstab to mount it at boot with its new device name and then
    Code:
    sudo mount -a
    and check it is correctly mounted

    Once all is ok,
    Code:
    sudo update-initramfs -u
    Last edited by YesWeCan; September 8th, 2011 at 02:18 AM.
    ASRock P67 Extreme6, Intel i5 2500K, 8GB RAM, nVidia 6600GT, 4x1TB RAID1+0

  4. #4
    Join Date
    Jan 2006
    Beans
    302

    Re: Partition 1 does not start on physical sector boundary.

    Quote Originally Posted by YesWeCan View Post
    Hey hows it going?
    so so. I lost all of my raid5 array :/ I thought it'd be a simple matter to "make a new one", but no :/

    Tumbleweed blowing through the thread?
    Yeah :/

    Do you want to erase all 3 disks and reformat them from scratch...you have everything backed up, right?
    What I have backed up, is what I have backed up. I am forced to make use of it now since the array is toast.

    I'd suggest

    Code:
    sudo dd if=/dev/zero of=/dev/sdx bs=1M count=100 conv=notrunc,noerror
    repeat for each drive

    Use Disk Utility to "format drive" and give each one a new MBR.
    Then "File", "Create" and have it make a RAID 5 for you:
    512 stripe size
    Give it a name (but do not use spaces or it screws up the mdadm.conf!)
    Select the 3 drives
    Then where the array size slider is, at the right is a box with the size. Round it down to the nearest 0.1GB by editing the number. Eg: If it says 2000.123GB then change it to 2000.1GB.
    Then set it going.

    It will give it an arbitrary device name that is not being used, /dev/mdN
    Click on the RAID device icon on the left and then the partition in the graphic and then "Format Volume".

    Finally, add the ARRAY directive to mdadm.conf.
    Code:
    sudo mdadm -Ds
    copy the line for the new RAID to mdadm.conf and change the device name to /dev/md? as you wish.
    Delete or comment out the old RAID5 one.

    Stop the array and reassemble it to make sure mdadm.conf is right
    Code:
    mdadm --stop /dev/mdN  (its current name)
    Code:
    mdadm -As
    check it reports assembling it with the device name you specified in mdadm.conf

    edit fstab to mount it at boot with its new device name and then
    Code:
    sudo mount -a
    and check it is correctly mounted

    Once all is ok,
    Code:
    sudo update-initramfs -u
    ok sounds like a plan...I'll get right to it this evening when I get home. Thanks for the detailed instructions!

    Max.

  5. #5
    Join Date
    Oct 2009
    Beans
    Hidden!
    Distro
    Ubuntu 12.04 Precise Pangolin

    Re: Partition 1 does not start on physical sector boundary.

    I've had the same thing happen with my 3TB external (4096 byte sectors). It's a problem with fdisk and the advanced format disks.
    Come to #ubuntuforums! We have cookies! | Basic Ubuntu Security Guide

    Tomorrow's an illusion and yesterday's a dream, today is a solution...

  6. #6
    Join Date
    Jan 2006
    Beans
    302

    Re: Partition 1 does not start on physical sector boundary.

    Quote Originally Posted by CharlesA View Post
    I've had the same thing happen with my 3TB external (4096 byte sectors). It's a problem with fdisk and the advanced format disks.
    and your solutions was...

  7. #7
    Join Date
    Mar 2007
    Location
    Portsmouth, UK
    Beans
    Hidden!
    Distro
    Ubuntu 11.10 Oneiric Ocelot

    Re: Partition 1 does not start on physical sector boundary.

    I know that gparted now has the option to correctly handle 4k; I thought that the current Ubuntu fdisk release also did - guess not!

    Would setting the start sector as 64 ( divisible by 8 ) not achieve correct alignment? I assume that formatting to 4096 size would also be recommended?

  8. #8
    Join Date
    Oct 2009
    Beans
    Hidden!
    Distro
    Ubuntu 12.04 Precise Pangolin

    Re: Partition 1 does not start on physical sector boundary.

    Quote Originally Posted by davidmaxwaterman View Post
    and your solutions was...
    Ignore it, gparted/parted said everything was fine. I ended up having to use the 10.10 version instead of 10.04 of parted/gparted tho (live cd ftw)

    Quote Originally Posted by Grenage View Post
    I know that gparted now has the option to correctly handle 4k; I thought that the current Ubuntu fdisk release also did - guess not!

    Would setting the start sector as 64 ( divisible by 8 ) not achieve correct alignment? I assume that formatting to 4096 size would also be recommended?
    When I used gparted, it correctly aligned the partition, I don't think the version in 10.04 did tho, as I had to use 10.10 to get it working.
    Come to #ubuntuforums! We have cookies! | Basic Ubuntu Security Guide

    Tomorrow's an illusion and yesterday's a dream, today is a solution...

  9. #9
    Join Date
    Jan 2006
    Beans
    302

    Re: Partition 1 does not start on physical sector boundary.

    Quote Originally Posted by Grenage View Post
    I know that gparted now has the option to correctly handle 4k; I thought that the current Ubuntu fdisk release also did - guess not!

    Would setting the start sector as 64 ( divisible by 8 ) not achieve correct alignment? I assume that formatting to 4096 size would also be recommended?
    well, i took your hint and went one better....i started the partition at 8 (also divisible by 8). seemed to work ok.

    i'm now wondering how best to test the file system i've put on top of it.

    i'm usind 'dd' to make a huge file, to see if i get any i/o errors...any other ideas?
    Last edited by CharlesA; September 10th, 2011 at 03:13 PM. Reason: fixed errant smiley

  10. #10
    Join Date
    Oct 2009
    Beans
    2,199
    Distro
    Ubuntu 10.10 Maverick Meerkat

    Re: Partition 1 does not start on physical sector boundary.

    http://www.ibm.com/developerworks/li...KB-Disksdth-LX

    I'm confused now. On an MBR format the first sector of the first partition is not supposed to start before 63. I'm surprised you were able to start a partition at 8. What tool did you use? Traditionally 63 is partition 1 start and now Windows tends to start it at 2048.

    Starting before 63 will create a problem for Grub because it needs this gap to embed itself. Not a concern in this case because I assme this RAID will not be used for booting.


    You might want to run e2fsck for peace of mind.
    ASRock P67 Extreme6, Intel i5 2500K, 8GB RAM, nVidia 6600GT, 4x1TB RAID1+0

Page 1 of 3 123 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •