Partition 1 does not start on physical sector boundary.

mshlinux · 11-04-2013, 10:37 PM

Windows 7 and Fedora 19 dual-boot on my desktop machine.
in Fedora 19, fdisk -l outputs

Code:

Disk /dev/sda: 500.1 GB, 500107862016 bytes, 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk label type: dos
Disk identifier: 0x2bd2c32a

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *          63   314584829   157292383+   7  HPFS/NTFS/exFAT
Partition 1 does not start on physical sector boundary.
/dev/sda2       314585088   874371119   279893016    7  HPFS/NTFS/exFAT
/dev/sda3       925573120   926597119      512000   83  Linux
/dev/sda4       926597120   976773167    25088024    5  Extended
/dev/sda5       926599168   934529023     3964928   82  Linux swap / Solaris
/dev/sda6       934531072   976773119    21121024   83  Linux

so, I googled about the message of Partition 1 does not start on physical sector boundary. to fix it.
the question is that
can I resize and move Partition 1 which holds Windows 7 in Fedora 19 using gparted? If I do so, Windows 7 won't boot?

pan64 · 11-05-2013, 01:11 AM

I'm afraid not, gparted will not able to do that. You need to use a partition manager like easeus partition master: http://www.partition-tool.com/

eumyang · 11-15-2013, 10:37 AM

Quote:

Originally Posted by mshlinux

so, I googled about the message of Partition 1 does not start on physical sector boundary. to fix it.

That's just a warning, it's not really a problem needing fixing. This shouldn't prevent your computer from running.

I do find it odd that partition 1 starts at sector 63. I think that if one installs Windows Vista or 7 and let the installer partition the disk, partition 1 would start at sector 2048 by default. If one installs Windows XP or earlier, partition 1 starts at sector 63 by default. Did this computer originally had XP or an older Windows OS, then later upgraded? Just curious.

Doug G · 11-15-2013, 12:25 PM

I recently configured a dell laptop that dual-boots windows 8 and fedora 19. I started by installing XP on a new hard drive, then upgraded to windows 8 from the w8pro dvd, and finally installed fedora 19 from dvd.

The windows partition starts at block 63 on my machine too, but I don't get any message about not starting on a sector boundary.

Code:

[root@d620 ~]# fdisk -l

Disk /dev/sda: 160.0 GB, 160041885696 bytes, 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0fc00fc0

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *          63   122881184    61440561    7  HPFS/NTFS/exFAT
/dev/sda2       122882048   123906047      512000   83  Linux
/dev/sda3       123906048   312457215    94275584   8e  Linux LVM

The difference seems to be the I/O size, I'm using 512-byte blocks

Ser Olmy · 11-15-2013, 12:43 PM

Quote:

Originally Posted by Doug G

The windows partition starts at block 63 on my machine too, but I don't get any message about not starting on a sector boundary.

Code:

[root@d620 ~]# fdisk -l

Disk /dev/sda: 160.0 GB, 160041885696 bytes, 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Your drive actually has 512 byte physical sectors.

The OP has a 4k sector drive ("advanced format") with 512 byte emulation, and his partition starts in the middle of a 4k sector. The file system blocks will be misaligned as well, which will hurt performance, especially writes.

mshlinux · 11-15-2013, 09:02 PM

Quote:

Originally Posted by Ser Olmy

Your drive actually has 512 byte physical sectors.

The OP has a 4k sector drive ("advanced format") with 512 byte emulation, and his partition starts in the middle of a 4k sector. The file system blocks will be misaligned as well, which will hurt performance, especially writes.

yes, that's right, it hurt performance, especially writes. in my experience, chrome, spreadsheet and other office programs frequently crash when they load two or three tasks at the same time. i suspect it is because of my partition error.

Ser Olmy · 11-15-2013, 09:13 PM

Quote:

Originally Posted by mshlinux

yes, that's right, it hurt performance, especially writes. in my experience, chrome, spreadsheet and other office programs frequently crash when they load two or three tasks at the same time. i suspect it is because of my partition error.

Misaligned sectors and file system fragments can make disk access (and hence the entire system) slower.

It will, however, NOT cause applications to crash or malfunction. If your system is unstable, partition alignment is not to blame.

mshlinux · 11-15-2013, 09:25 PM

Quote:

Originally Posted by Ser Olmy

Misaligned sectors and file system fragments can make disk access (and hence the entire system) slower.

It will, however, NOT cause applications to crash or malfunction. If your system is unstable, partition alignment is not to blame.

ohh! really? thanks for ur sharing knowledge.
so, i think i should forget about this partition error because this is office computer.
i don't wanna take risk messing partitions which can break MBR.

rknichols · 11-16-2013, 09:14 AM

The misalignment will affect write operations, hurting write performance by a factor of 10 or more. The effect on read operations is minimal.

Doug G · 11-16-2013, 10:51 PM

Quote:

Your drive actually has 512 byte physical sectors.

That's what I said.

I was just trying to point out the windows installer was probably what put the NTFS partition where it is. I would guess windows wouldn't care if you moved the partition to get rid of the error message, but the windows bootloader might care.