Cannot Create Partition

Cannot Create Partition

[CACook]

On /dev/sda I have sda1 which is my / bootable filesystem for Debian formatted ext4.  This is 256MB on a 2TB drive.

I want to set up the rest of the drive as BTRFS for various functions, and I presume that I first have to create a partition using fdisk for this?  Since my first part is ext4?  So I:
# fdisk /dev/sda
WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').
Command (m for help): p
Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1      243202  1953514583+  ee  GPT
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 2
No free sectors available
Command (m for help):
-------------------------------------------------
Whaa?

Maybe it's possible that I just mkfs.btrfs /dev/sda and it will set up -only- the remaining space, but I'm afraid that this may destroy my OS.

Also, what if I want to set up the whole drive as BTRFS?  Could this be bootable, and can the canned Debian kernel load the BTRFS driver for boot at install?  Or would I boot to the CD, mkfs.btrfs the drive, then install Debian?  Anyone tried this?

Re: Cannot Create Partition

[Hugo Mills]

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On Sun, Jan 23, 2011 at 10:07:54AM -0800, CACook@quantum-sci.com wrote:
> 
> On /dev/sda I have sda1 which is my / bootable filesystem for Debian formatted ext4.  This is 256MB on a 2TB drive.
> 
> I want to set up the rest of the drive as BTRFS for various functions, and I presume that I first have to create a partition using fdisk for this?  Since my first part is ext4?  So I:
> # fdisk /dev/sda
> WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.

   I think the above may be the root cause of your problem. You're
using the new GPT partition table format, not the traditional DOS one,
and fdisk is claiming that it can't handle it.

> WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
>          switch off the mode (command 'c') and change display units to
>          sectors (command 'u').
> Command (m for help): p
> Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
> 255 heads, 63 sectors/track, 243201 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x00000000
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sda1               1      243202  1953514583+  ee  GPT
> Command (m for help): n
> Command action
>    e   extended
>    p   primary partition (1-4)
> p
> Partition number (1-4): 2
> No free sectors available
> Command (m for help):
> -------------------------------------------------
> Whaa?
> 
> Maybe it's possible that I just mkfs.btrfs /dev/sda and it will set
> up -only- the remaining space, but I'm afraid that this may destroy
> my OS.

   No, that will almost certainly destroy your existing partitioning,
and hence, as you say, your OS install.

> Also, what if I want to set up the whole drive as BTRFS?  Could this
> be bootable, and can the canned Debian kernel load the BTRFS driver
> for boot at install?  Or would I boot to the CD, mkfs.btrfs the
> drive, then install Debian?  Anyone tried this?

   As far as I know, GRUB2 doesn't yet support btrfs (although there
was some work done on it, I don't know what the status of that work
is). This means that you need a filesystem of some other type to boot
off -- even if it only holds the contents of /boot. There are
certainly people around who've done this, although I'm not one of
them.

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
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Re: Cannot Create Partition

[Fajar A. Nugraha]

On Mon, Jan 24, 2011 at 1:07 AM,  <CACook@quantum-sci.com> wrote:
>
> On /dev/sda I have sda1 which is my / bootable filesystem for Debian =
formatted ext4. =A0This is 256MB on a 2TB drive.

Really? How do you know it's 256 MB?

> # fdisk /dev/sda
> WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util =
fdisk doesn't support GPT. Use GNU Parted.
> WARNING: DOS-compatible mode is deprecated. It's strongly recommended=
 to
> =A0 =A0 =A0 =A0 switch off the mode (command 'c') and change display =
units to
> =A0 =A0 =A0 =A0 sectors (command 'u').
> Command (m for help): p
> Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
> 255 heads, 63 sectors/track, 243201 cylinders
> Units =3D cylinders of 16065 * 512 =3D 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x00000000
> =A0 Device Boot =A0 =A0 =A0Start =A0 =A0 =A0 =A0 End =A0 =A0 =A0Block=
s =A0 Id =A0System
> /dev/sda1 =A0 =A0 =A0 =A0 =A0 =A0 =A0 1 =A0 =A0 =A0243202 =A019535145=
83+ =A0ee =A0GPT

=2E.. cause the fdisk output pretty much shows the first partition uses
up all space.
You can check again if you want, using "parted /dev/sda print" (just
in case it's really fdisk problem).

> Maybe it's possible that I just mkfs.btrfs /dev/sda and it will set u=
p -only- the remaining space, but I'm afraid that this may destroy my O=
S.

You might be able to boot using a live CD and use gparted to resize
the current ext4 partition.

>
> Also, what if I want to set up the whole drive as BTRFS? =A0Could thi=
s be bootable, and can the canned Debian kernel load the BTRFS driver f=
or boot at install? =A0Or would I boot to the CD, mkfs.btrfs the drive,=
 then install Debian? =A0Anyone tried this?

Ubuntu Natty's grub2 has btrfs support, but It's still in alpha stage
though. Don't know about Debian.
At this point it's easiest if you use ext3/4 for /boot, and use btrfs
only for "/".

--=20
=46ajar
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Re: Cannot Create Partition

[Michael Milligan]

CACook@quantum-sci.com wrote:
> On /dev/sda I have sda1 which is my / bootable filesystem for Debian formatted ext4.  This is 256MB on a 2TB drive.
> 
> I want to set up the rest of the drive as BTRFS for various functions, and I presume that I first have to create a partition using fdisk for this?  Since my first part is ext4?  So I:
> # fdisk /dev/sda
> WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.

Do exactly as you are instructed here.  Use parted.  fdisk doesn't
support GPT partition tables, only MS-DOS tables.

# parted /dev/sda
GNU Parted 2.3
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) []

Now, type "help" if you are stumped.  Or perhaps "man parted".  Or even
use gparted since that's the graphical version and much easier to drive.

Regards,
Mike