Linux partition misaligned?

[cozumel]

Hi,

I am totally new to Linux, so please be gentle with me!;)

I have installed 11.10 x64 alongside Windows 7 x64

My Hard Drive is a Western Digital Scorpio WD5000BPKT-75PK4T0

When I look at my partitions through disk utility that came with ubuntu and click on the Linux partition it says:
"WARNING: The partition is misaligned by 1024 bytes. This may result in very poor performance. Repartitioning is suggested."

Does this mean I should delete the partition, resize and reinstall?

Thanks for your help? (Sorry to be such a noob lol)

[Bmonsterboy]

Hey don't be so harsh on yourself. Everyone had to be a beginner once too :)
This might help: http://ubuntuforums.org/showthread.php?t=1635018

[westie457]

Hello and welcome to the Forum.

Before doing anything drastic and time consuming take a look at this thread and the links within it. http://ubuntuforums.org/showthread.php?t=1635018
A lot of reading and information to digest.

Reformatting and re-installing will work however that is usually the 'when all else fails' option.

[cozumel]

Thanks gentlemen (or ladies) for your snappy replies and link(s).

Okay, just checked and my disk is Advanced Format (oh joy)

I'll download paragon alignment tool and then hopefully realign and validate correct alignment.

I'll post back if I am successful or have any further problems

Thanks again guys (or gals) :D

[mastablasta]

gparted should have done the alignment. Is this still not done automaticly by it??!?!

[cozumel]

gparted should have done the alignment. Is this still not done automaticly by it??!?!I used gparted via the terminal from the livecd 11.10 to resize original partitions and create new partitions for Ubuntu. So, it is either not automated or I did something wrong..

[mastablasta]

hmm i don't have the ubuntu near me now, so i am hoping someone will explain or reply to this. i somehow understoong this is done in gparted.

Also you used gparted to shrink windows partition? then consider yourself lucky. oherwise this is better done with windows disk manager, as windows partition and gparted mix is not always a sucess. it is most of the time, but now always.

[cozumel]

Also you used gparted to shrink windows partition? then consider yourself lucky. oherwise this is better done with windows disk manager, as windows partition and gparted mix is not always a sucess. it is most of the time, but now always.I read that in various places/forums/sites. I chose to ignore and use gparted as the whole point is to learn. If I stick to using using Windows programs then I don't gain knowledge. Basically thought to myself "what the heck. Use linux to partition" lol

I did create image of win7 installation and backup important files first though

[cozumel]

Okay.

So I ran both Paragon Alignment Utility (PAT) and Dells Advance Format Detection Utility (AFDU), both from within Win7. They both say all partitions are correctly aligned. But Linux disagrees.

Any ideas please?

[cozumel]

Here is the output from "sudo fdisk -lu" and shows what Linux sees.


Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 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 identifier: 0x07f2837e

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT
/dev/sda2 206848 949430271 474611712 7 HPFS/NTFS/exFAT
/dev/sda3 949432318 976771071 13669377 5 Extended
Partition 3 does not start on physical sector boundary.
/dev/sda5 949432320 968599551 9583616 83 Linux
/dev/sda6 968601600 976771071 4084736 82 Linux swap / Solaris

Actually, think I'll reboot into livecd and see if I can adjust partition size with gparted

[oldfred]

If all the starts of your partitions can be divided by 8 then you do not have a problem.

srs5694's to show 8 sector alignment post #9
http://ubuntuforums.org/showthread.php?t=1685666
$ sudo parted /dev/sda unit s print

First, understand that most partitioning tools have moved to a policy of aligning partitions on 1 MiB (2048-sector) boundaries as a way of improving performance with some types of RAID arrays and some types of new hard disks (those with 4096-byte physical sectors). See article by srs5694:
http://www.ibm.com/developerworks/linux/library/l-4kb-sector-disks/

[cozumel]

Thanks oldfred. I worked out a while ago about the start point having to be a multiple of 8. Had my calculator out and new where I want it to begin. Just don't know how to create the partition correctly aligned.

Since my last post I deleted Linux partitions with gparted and reduced the size of Windows partition.

I then manually created a knew extended partition with gparted. First time align with MiB and misaligned so deleted. Then align with cylinders and misaligned so deleted. Then align with option 'none' and I got a multiple of 8. Great! :)

Then tried to install with live disk and paused install when asks me to input username etc. Checked again with fdisk now the installer has created logical partitions and my extended partition has slightly resized and is no longer aligned. "Partition 3 does not start on physical sector boundary"

So, I'm back to where I started lol.

If it comes down to it, Ill wipe Windows, Linux and reformat the lot. But I would prefer to learn what I am doing wrong as it obviously me doing to much of a noob with Linux and doing it all wrong.

Any suggestions please how to get my magical multiple of 8 pls :D

If anyone could walk me through it would really be appreciate as this is way beyond my current knowledge (but I'm eager to learn and am willing student)

[oldfred]

If partition 3 is your extended partition then it is not important.

Is errors sector boundry or cylinder. Old fdisk still refers to cylinders even though cylinders have not been used for years (Since LBA with drives over 8GB).

[lobos marinos]

deleted

[cozumel]

Hi, Partition 3 is the extended partion and is marked on Linux as misaligned. Partions 4 & 5 are the linux system and swap, they are correctly aligned.

Are you saying that the only important factor is to have the logical partitions aligned correctly with the physical sector edge as they are the partitions that hold (store) the data? Are you also saying because the extended partition does not actually hold the data, aligning is irrelevant?

If you can confirm both of these questions then I can mark as solved.

Thanks again for help.

[oldfred]

You do not write in the extended partition but the logical inside it, so only the logicals have to be aligned.

Even a small boot partition that you almost always just read from does not have to be aligned. It is the writes that you have to worry about.

I prefer to use gpt as then all partitions are primary, but in BIOS mode you cannot use gpt with Windows. So I have several drives, some still MBR and some gpt.

[cozumel]

Thanks. Marked as solved!! :)