creates a misaligned partition

[Martin Pool]

Binary package hint: gnome-disk-utility

I installed a new 750GB disk in the expansion bay of my X201, and then used Maverick's disk-utility to create a GUID Partition Table.
I then made a new 250GB partition at the start of the disk. Next time I opened disk-utility, I saw a warning: "the partition is misaligned by 3072 bytes. This may result in very poor performance. Repartitioning is suggested."

I then deleted the partition, created a new one, and found the exact same problem occurs.

1- If disk-utility is smart enough to know this partition layout will cause poor performance, it shouldn't create it!
2- Does this actually cause poor performance on modern hardware/kernels?

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: gnome-disk-utility 2.30.1-2
ProcVersionSignature: Ubuntu 2.6.35-28.50-generic 2.6.35.11
Uname: Linux 2.6.35-28-generic x86_64
Architecture: amd64
Date: Fri Mar 25 09:48:06 2011
EcryptfsInUse: Yes
ExecutablePath: /usr/lib/gnome-disk-utility/gdu-notification-daemon
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
ProcEnviron:
 PATH=(custom, user)
 LANG=en_AU.utf8
 SHELL=/bin/zsh
SourcePackage: gnome-disk-utility

[Martin Pool (mbp)]

I guess this may actually be a reflection of parted half-supporting 4kb alignment?

The device reports:

mbp@joy% cat alignment_offset queue/minimum_io_size queue/max_segment_size queue/physical_block_size queue/optimal_io_size
0
4096
65536
4096
0

[Colin Watson (cjwatson)]

libparted should fully support 4kb alignment, although the application using it does have to switch it into the right mode. Maybe gnome-disk-utility is doing it wrong.

[Martin Pool (mbp)]

see also bug 742164

[Darxus (darxus)]

Getting "The partition is misaligned by 506880 bytes." 4tb partition on a raid 0 of two 2tb drives, created by palimpsest (gnome disk utility). On Oneric.

[Ed Williams (ed-williams)]

I also get this bug on a newly installed 12.4 with Seagate ST2000DM001 drives. Reported misalignment is 3072 bytes. Both drives work and pass all diagnostics, but average seek time is 14.2 to 14.4 ms.

based on question 184477 I ran
sudo fdisk -l; mount; echo; lsb_release -a; uname -a
and got

WARNING: GPT (GUID Partition Table) detected on '/dev/sdc'! The util fdisk doesn't support GPT. Use GNU Parted.

Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 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 identifier: 0x00000000

   Device Boot Start End Blocks Id System
/dev/sdc1 1 3907029167 1953514583+ ee GPT
Partition 1 does not start on physical sector boundary.

WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.

Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 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 identifier: 0x00000000

   Device Boot Start End Blocks Id System
/dev/sdb1 1 3907029167 1953514583+ ee GPT
Partition 1 does not start on physical sector boundary.
/dev/sda1 on / type ext4 (rw,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
udev on /dev type devtmpfs (rw,mode=0755)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)
none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)
none on /run/shm type tmpfs (rw,nosuid,nodev)
gvfs-fuse-daemon on /home/nas/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=nas)
/dev/sdc1 on /media/2TB type ext4 (rw,nosuid,nodev,uhelper=udisks)
/dev/sdb1 on /media/2TA type ext4 (rw,nosuid,nodev,uhelper=udisks)

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04 LTS
Release: 12.04
Codename: precise
Linux nas 3.2.0-27-generic-pae #43-Ubuntu SMP Fri Jul 6 15:06:05 UTC 2012 i686 i686 i386 GNU/Linux

[Ed Williams (ed-williams)]

This PC runs only 12.4, and boots from a smaller 3rd disk, not these disks. I have nothing on these disks yet, so am will to try anything.

[Joost Ringoot (joost)]

IMHO these bugs appear to point to the same root cause:

https://bugs.launchpad.net/ubuntu/+source/gnome-disk-utility/+bug/1034609
and
https://bugs.launchpad.net/ubuntu/+source/parted/+bug/742164