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crispin

Member

Registered: 2011-02-14

Posts: 8

[SOLVED] Are fdisk number values reliable?

Hi there

I'd like to repartition my disk. I'm not touching partition locations, neither data, nor headers, I only plan to alter the partition table. This is how the current table looks:

Disposit. Inicio    Comienzo      Fin      Bloques  Id  Sistema
/dev/sda1            2048   976773167   488385560    5  Extendida
/dev/sda5            4096   167776255    83886080   83  Linux
/dev/sda6       167778304   335550463    83886080   83  Linux
/dev/sda7       335552512   503324671    83886080   83  Linux
/dev/sda8       503326720   671098879    83886080   83  Linux
/dev/sda9       671100928   838873087    83886080   83  Linux
/dev/sda10      838875136   976773167    68949016   83  Linux

I plan to remove the first logical partition and replace it with a physical one.

Disposit. Inicio    Comienzo      Fin      Bloques  Id  Sistema
/dev/sda1            2048   167774208    83886080+  83  Linux
/dev/sda2       167776256   976773167   404498456    5  Extendida
/dev/sda5       167778304   335550463    83886080   83  Linux
/dev/sda6       335552512   503324671    83886080   83  Linux
/dev/sda7       503326720   671098879    83886080   83  Linux
/dev/sda8       671100928   838873087    83886080   83  Linux
/dev/sda9       838875136   976773167    68949016   83  Linux

The tables you see here are from a dry run of the scenario with fdisk. As far as I can see, the new /dev/sda5 starts where /dev/sda6 used to be. Like I intended.

Are these values I get from fdisk accurate? In other words: Is the start of the old /dev/sda6 exactly at the same bit as the start of the new /dev/sda5, like the numbers suggest?

Thanks in advance,
Crispin

Last edited by crispin (2013-03-13 23:27:15)

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: [SOLVED] Are fdisk number values reliable?

Yes they are accurate.

It appears you are using only Linux. Why not do yourself the favor of switching to GPT and never having to deal with extended partitions again?

Also why are you trying to make this change? What advantage does it bring or what is it you are trying to solve?

srs5694

Member

From: Woonsocket, RI

Registered: 2012-11-06

Posts: 719

Website

Re: [SOLVED] Are fdisk number values reliable?

WonderWoofy makes valid points. One more: This type of conversion can be done a little more easily with my FixParts program, which is part of the gptfdisk package in Arch. The gdisk program in the same package can do a lossless MBR-to-GPT conversion, too, although you'll need to re-install your boot loader after doing such a conversion. If you use GRUB, you'd be well advised to create a BIOS Boot Partition for its use.

crispin

Member

Registered: 2011-02-14

Posts: 8

Re: [SOLVED] Are fdisk number values reliable?

Thanks for the replies.

The reason the partition change is that I need some space (primary partition) for a windows install. The reason for using MBR is that I anticipated this when I setted up my current installation. I only missed the point that Windows needs a primary partition to install to ;-)

srs5694

Member

From: Woonsocket, RI

Registered: 2012-11-06

Posts: 719

Website

Re: [SOLVED] Are fdisk number values reliable?

In that case, use GParted to resize and/or move partitions as necessary and then create a new primary partition. (You'll need to resize the extended partition that houses the logicals, too.) There's no need to convert an existing partition to primary unless you want to remove it entirely from Linux's use and give it to Windows -- and in that case, you could just delete it and resize the surrounding extended partition to make room for a new primary for Windows.

crispin

Member

Registered: 2011-02-14

Posts: 8

Re: [SOLVED] Are fdisk number values reliable?

Hi srs5694

I'm sorry if you feel ignored, I'm not around the forums every day and did not look into this thread because I considered this question solved. Thank you for your help, it's appreciated.

Crispin