Potential F14 feature: Use GPT partition table by default for "wipe complete HD" installations

[Till Maas]

Hi,

how about using GPT[0] partitions for F14 for all installations that wipe
the whole disk to install Fedora? It is also considered to be good by
Tejun Heo[1] and it seems to work nicely already on F12. I just
partitioned a new HD using gdisk and the kernel seems to recognise it
without any problems.

Regards
Till

[0] http://de.wikipedia.org/wiki/GUID_Partition_Table
[1]
http://ata.wiki.kernel.org/index.php/ATA_4_KiB_sector_issues#Random_thoug...

[Matt Domsch]

On Thu, Mar 18, 2010 at 09:55:37PM +0100, Till Maas wrote:
>  Hi,
>  
>  how about using GPT[0] partitions for F14 for all installations that wipe
>  the whole disk to install Fedora? It is also considered to be good by
>  Tejun Heo[1] and it seems to work nicely already on F12. I just
>  partitioned a new HD using gdisk and the kernel seems to recognise it
>  without any problems. 
Very few BIOSes can boot from a GPT disk.  EFI/UEFI can, as can legacy
BIOS if you do something ugly like gptsync so the MBR partition table
and the GPT partition table at least somewhat agree.

-- 
Matt Domsch
Technology Strategist, Dell Office of the CTO
linux.dell.com & www.dell.com/linux

[John Reiser]

On 03/18/2010 09:25 PM, Matt Domsch wrote:
>  Very few BIOSes can boot from a GPT disk.  EFI/UEFI can, as can
> legacy
>  BIOS if you do something ugly like gptsync so the MBR partition table
>  and the GPT partition table at least somewhat agree. 
Does this mean that the presence of a GPT partition table somehow prevents
the BIOS from reading the first sector into memory, jumping to it,
and afterwards reading other sectors (with LBA48 addresses) into memory?

--

[Karel Zak]

On Thu, Mar 18, 2010 at 11:25:45PM -0500, Matt Domsch wrote:
>  On Thu, Mar 18, 2010 at 09:55:37PM +0100, Till Maas wrote:
>  > Hi,
>  > 
>  > how about using GPT[0] partitions for F14 for all installations that wipe
>  > the whole disk to install Fedora? It is also considered to be good by
>  > Tejun Heo[1] and it seems to work nicely already on F12. I just
>  > partitioned a new HD using gdisk and the kernel seems to recognise it
>  > without any problems.
>  
>  Very few BIOSes can boot from a GPT disk.  
 Urban legend...

>  EFI/UEFI can, as can legacy
>  BIOS if you do something ugly like gptsync so the MBR partition table
>  and the GPT partition table at least somewhat agree. 
 The problem is old grub.

    Karel

-- 
 Karel Zak  <kzak(a)redhat.com&gt;

[Maxim Burgerhout]

>   The problem is old grub. 
To quickly hook into this: wouldn't moving to grub2 be a viable
feature for F14 then? I know we wouldn't be the first to do it, but
that might be a plus here. The Ubuntu guys have already forced some
more wide spread testing of grub2 by implementing it in a recent
release. Implementing grub2 might then eventually make implementing
GPT in a later phase an option (I am not qualified to state this as a
certainty).

Or has this all been talked about before and has already been
concluded that this is not viable?

Maxim Burgerhout
maxim(a)wzzrd.com
----------------
GPG Fingerprint
EB11 5E56 E648 9D99 E8EF 05FB C513 6FD4 1302 B48A

[Till Maas]

On Fri, Mar 19, 2010 at 10:34:59AM +0100, Karel Zak wrote:
>  On Thu, Mar 18, 2010 at 11:25:45PM -0500, Matt Domsch wrote:
>  > On Thu, Mar 18, 2010 at 09:55:37PM +0100, Till Maas wrote:
>  > > Hi,
>  > > 
>  > > how about using GPT[0] partitions for F14 for all installations that wipe
>  > > the whole disk to install Fedora? It is also considered to be good by
>  > > Tejun Heo[1] and it seems to work nicely already on F12. I just
>  > > partitioned a new HD using gdisk and the kernel seems to recognise it
>  > > without any problems.
>  > 
>  > Very few BIOSes can boot from a GPT disk. 
>  
>   Urban legend... 
I am also pretty sure that a BIOS does not consider the partition table
to boot, because it only needs to access the first 440 (maybe 446) bytes
of hard disk, which will not be touched by GPT:
http://en.wikipedia.org/wiki/Master_boot_record

>  > EFI/UEFI can, as can legacy
>  > BIOS if you do something ugly like gptsync so the MBR partition table
>  > and the GPT partition table at least somewhat agree.
>  
>   The problem is old grub. 
But the Fedora grub is supposed to support it for a long time:
| * Mon Jul 16 2007 Peter Jones <pjones redhat com> - 0.97-15
| - Support booting from GPT

Regards
Till

[Manuel Wolfshant]

Till Maas wrote:
>  On Fri, Mar 19, 2010 at 10:34:59AM +0100, Karel Zak wrote:
>    
> > On Thu, Mar 18, 2010 at 11:25:45PM -0500, Matt Domsch wrote:
> >     
> >> On Thu, Mar 18, 2010 at 09:55:37PM +0100, Till Maas wrote:
> >>       
> >>> Hi,
> >>>
> >>> how about using GPT[0] partitions for F14 for all installations that wipe
> >>> the whole disk to install Fedora? It is also considered to be good by
> >>> Tejun Heo[1] and it seems to work nicely already on F12. I just
> >>> partitioned a new HD using gdisk and the kernel seems to recognise it
> >>> without any problems.
> >>>         
> >> Very few BIOSes can boot from a GPT disk. 
> >>       
> >  Urban legend...
> >     
>
>  I am also pretty sure that a BIOS does not consider the partition table
>  to boot, 
I can vouch for at least 2 Intel based motherboards which do not boot 
unless a) there exists a partition table and b) one partition is marked 
as active

however, to be honest, those are OLD mobos and probably not relevant any 
more

[Till Maas]

On Fri, Mar 19, 2010 at 12:22:56PM +0200, Manuel Wolfshant wrote:
>  Till Maas wrote:
>  > On Fri, Mar 19, 2010 at 10:34:59AM +0100, Karel Zak wrote: 
>  > I am also pretty sure that a BIOS does not consider the
> partition table
>  > to boot,
>  I can vouch for at least 2 Intel based motherboards which do not boot 
>  unless a) there exists a partition table and b) one partition is marked 
>  as active 
There still will be a partition table, but it will always show a
partition that starts at sector 1. By default it seems not to be marked
as active, but this should be possible. This is then the old style
partition, that contains the new GPT header and partitions.

Regards
Till

[David Woodhouse]

On Thu, 2010-03-18 at 21:55 +0100, Till Maas wrote:
>  how about using GPT[0] partitions for F14 for all installations that
> wipe
>  the whole disk to install Fedora? It is also considered to be good by
>  Tejun Heo[1] and it seems to work nicely already on F12. I just
>  partitioned a new HD using gdisk and the kernel seems to recognise it
>  without any problems.  
Are there any good reasons to do this _other_ than so we can cope with
larger disks?

How about doing it only for disks which are too large to cope with the
DOS-style partition tables?

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse(a)intel.com                              Intel Corporation

[Till Maas]

On Fri, Mar 19, 2010 at 01:04:29PM +0000, David Woodhouse wrote:
>  On Thu, 2010-03-18 at 21:55 +0100, Till Maas wrote:
>  > how about using GPT[0] partitions for F14 for all installations that wipe
>  > the whole disk to install Fedora? It is also considered to be good by
>  > Tejun Heo[1] and it seems to work nicely already on F12. I just
>  > partitioned a new HD using gdisk and the kernel seems to recognise it
>  > without any problems. 
>  
>  Are there any good reasons to do this _other_ than so we can cope with
>  larger disks? 
Afaik it is also required in case one uses EFI instead of a BIOS. Doing
this soon would make Fedora ready once it is required. Other nice
features are checksums for the partition table and file system
independent uuids for the partitions and file system independent clear
text names for partitions. These can be used to easier identify
partitions that do not contain a file system, e.g. because they are
encrypted or they have been wiped. Then they could be easier identified
to be used again, e.g. in the installer.

>  How about doing it only for disks which are too large to cope with
> the
>  DOS-style partition tables? 
For large disks it would be required anyhow. But it does not need to be
default, at least support for it in the installer would be nice.

Regards
Till

[Jesse Keating]

On Fri, 2010-03-19 at 13:04 +0000, David Woodhouse wrote:
>  Are there any good reasons to do this _other_ than so we can cope
> with
>  larger disks?
>  
>  How about doing it only for disks which are too large to cope with the
>  DOS-style partition tables?
>  
>   
Why deal with two different types of partitioning tables?  Why /not/ go
forward to GPT, I think that's the more appropriate question.

-- 
Jesse Keating
Fedora -- Freedom² is a feature!
identi.ca: http://identi.ca/jkeating

[Jochen Schmitt]

Am 19.03.10 17:52, schrieb Jesse Keating:
>  Why deal with two different types of partitioning tables?  Why /not/
> go
>  forward to GPT, I think that's the more appropriate question.
>
>      
No all operating systems are able to support GPT, so there may be nice 
to have
a hybrid partition schema.

Aspecial if you want a tripple boot system on a Macaintosh system, there 
will be
nice to have this feature, because you can only have four partition in 
the MBR, which
may be assigned as follow:

Partitiona #1    EFI system partition
Partition #2:    Mac OX X
Partition #3:    Linux
Partition #4:    Windows

Anyone in the future we may not have this discussion because all 
computer have moved
to a UEFI systen caused by the 2 TB limitation of the MBR partition 
schea, but now we
have the issue, that we have to support OS which are unable to support 
GPT partition
hard discs.

Best Regards:

Jochen Schmitt

[Richard W.M. Jones]

On Thu, Mar 18, 2010 at 09:55:37PM +0100, Till Maas wrote:
>  Hi,
>  
>  how about using GPT[0] partitions for F14 for all installations that wipe
>  the whole disk to install Fedora? It is also considered to be good by
>  Tejun Heo[1] and it seems to work nicely already on F12. I just
>  partitioned a new HD using gdisk and the kernel seems to recognise it
>  without any problems. 
Yes!

Hopefully BIOS support won't be a problem because of gptsync.  Can we
also get gptsync packaged separately, instead of having an odd version
bundled with Anaconda ...

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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programs, test, and build Windows installers. Over 70 libraries supprt'd
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[Till Maas]

On Fri, Mar 19, 2010 at 07:54:09PM +0000, Richard W.M. Jones wrote:

>  Yes!
>  
>  Hopefully BIOS support won't be a problem because of gptsync.  Can we
>  also get gptsync packaged separately, instead of having an odd version
>  bundled with Anaconda ... 
A first incomplete Feature page is available here:
https://fedoraproject.org/wiki/Features/GUID_Partition_Table

Regards
Till

[Richard W.M. Jones]

On Fri, Mar 19, 2010 at 09:39:05PM +0100, Till Maas wrote:
>  On Fri, Mar 19, 2010 at 07:54:09PM +0000, Richard W.M. Jones wrote:
>  
>  > Yes!
>  > 
>  > Hopefully BIOS support won't be a problem because of gptsync.  Can we
>  > also get gptsync packaged separately, instead of having an odd version
>  > bundled with Anaconda ...
>  
>  A first incomplete Feature page is available here:
>  https://fedoraproject.org/wiki/Features/GUID_Partition_Table 
I added a section summarising the issues with gptsync AIUI:

https://fedoraproject.org/wiki/Features/GUID_Partition_Table#gptsync

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming blog: http://rwmj.wordpress.com
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