Arch Linux

SolarBoyMatt

Member

Registered: 2012-01-07

Posts: 263

[SOLVED] Misaligned Partitions?

Today when I checked the Disk Utility on GNOME, it's telling me that some of my partitions are misaligned. My /boot at /dev/sda1 is misaligned by 512 bytes, my Swap on /dev/sda2 by 1563 bytes, and my root parition by 1024 bytes. My /home partition is fine for some reason though. I'm not sure if this happened during installation or because of resizing root partition afterwards, for whatever reason.

I loaded up my gparted live disc, but I can't seem find any way to "realign" them, and none of them can be moved.

Is this something to be concerned about, and if so, is there a way to fix this without doing a fresh install or something? I'd prefer not to, but this install is less than a week old, so I could manage I guess.

Last edited by SolarBoyMatt (2012-01-20 20:36:40)

piratebill

Member

From: Sol System

Registered: 2011-10-20

Posts: 133

Re: [SOLVED] Misaligned Partitions?

This might help http://ubuntuforums.org/showthread.php?t=1863784

be prepared for a lot of reading.

SolarBoyMatt

Member

Registered: 2012-01-07

Posts: 263

Re: [SOLVED] Misaligned Partitions?

According to a post in a thread linked to in that one, this happens on certain WD Drives, which have something called "Advanced Format". My drive seems to be one of those, but from what I gather from this http://www.ibm.com/developerworks/linux … tor-disks/ the only issue really seems to be read and write performance, and on ext4, which is what my root partition is using there doesn't seem to be a huge decrease in performance, and I certainly haven't noticed it either if there has been.

Another reason I asked if this was an issue, was because last night when I updated to Kernel 3.1.8-1, pacman was saying my /boot partition was not mounted, even though it was, and that I may have broken my system. But when I rebooted, everything started up fine and nothing was broken, and I'm currently using the 3.1.8-1 Kernel. So I guess that might be another issue in and of itself then?

Last edited by SolarBoyMatt (2012-01-12 00:13:10)

thetrivialstuff

Member

Registered: 2006-05-10

Posts: 191

Re: [SOLVED] Misaligned Partitions?

According to a post in a thread linked to in that one, this happens on certain WD Drives, which have something called "Advanced Format". My drive seems to be one of those, but from what I gather from this http://www.ibm.com/developerworks/linux … tor-disks/ the only issue really seems to be read and write performance

Correct -- performance should be the only thing affected by not lining up to the 4k sectors. As I recall, the issue with those WD drives isn't so much the 4k sectors, but that they report themselves as having 512-byte sectors (i.e., the drive firmware lies to the OS about it).

I also haven't really noticed performance problems on machines with misaligned partitions -- I suspect that the performance hit from misaligned sectors is less severe than the overall speed limits of writing to spinning magnetic disks  

Another reason I asked if this was an issue, was because last night when I updated to Kernel 3.1.8-1, pacman was saying my /boot partition was not mounted, even though it was, and that I may have broken my system. But when I rebooted, everything started up fine and nothing was broken, and I'm currently using the 3.1.8-1 Kernel. So I guess that might be another issue in and of itself then?

If your system properly used the new kernel after the reboot, then yes, pacman was wrong to complain and that's possibly a pacman bug. I've only ever seen that error message when I had indeed forgotten to mount /boot before upgrade, though -- is there anything unusual about your /etc/fstab that might've confused it?

SolarBoyMatt

Member

Registered: 2012-01-07

Posts: 263

Re: [SOLVED] Misaligned Partitions?

I was just going to post here saying I've had no issues regarding this. So I'll mark this as solved then. Thanks!

Also, about that Kernel update issue, I haven't touched my fstab file so there shouldn't be anything weird about it. This didn't happen when I updated to the 3.1.9-1 kernel, so I'm not sure what that error was all about.

Last edited by SolarBoyMatt (2012-01-20 20:55:37)