[gentoo-user] fdisk errors after repartitioning

[gentoo-user] fdisk errors after repartitioning

[Robert G. Siebeck]

Hi,

I recently repartitioned my harddisk. Before my HD had 4 partitions,
all primary ones: boot, swap, Linux (Reiserfs) and Windows (FAT32).
I shrinked the reiserfs-partition and then deleted it. I deleted swap,
too. Then I created an extended partition. Within this extended
partition I created a new logical partition which had the same start
and end cylinders as the resized Reiserfs partition. Further I created
a new swap partition within the extended partition and created a
(primary) partition for FreeBSD on the place freed by resizing the
Reiser-partition.
Actually everything seems to work, I'm not missing any files and all
systems (Linux, FreeBSD and Windows) work fine.
The only thing which seems strange is an error thrown by fdisk:


# fdisk /dev/hda

The number of cylinders for this disk is set to 116280.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

Disk /dev/hda: 60.0 GB, 60011642880 bytes
16 heads, 63 sectors/track, 116280 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1               1         130       65488+  83  Linux
Partition 1 does not end on cylinder boundary.
/dev/hda2             131       79717    40111848    5  Extended
Partition 2 does not end on cylinder boundary.
/dev/hda3   *       79718       95960     8186314+  a5  FreeBSD
Partition 3 does not end on cylinder boundary.
/dev/hda4           95964      116279    10239264    c  W95 FAT32 (LBA)
Partition 4 does not end on cylinder boundary.
/dev/hda5            2212       79717    39063024   83  Linux
/dev/hda6             131        2211     1048792+  82  Linux swap / Solaris


cfdisk doesn't even start but stops with the following message:

FATAL ERROR: Bad logical partition 6: enlarged logical partitions overlap
Press any key to exit cfdisk


Do you have any ideas how I could get rid of these messages?
Thanks in advance!

Regards,

Robert.

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Re: [gentoo-user] fdisk errors after repartitioning

[Richard Fish]

Robert G. Siebeck wrote:

>The only thing which seems strange is an error thrown by fdisk:
>
>
># fdisk /dev/hda
>
>The number of cylinders for this disk is set to 116280.
>There is nothing wrong with that, but this is larger than 1024,
>and could in certain setups cause problems with:
>1) software that runs at boot time (e.g., old versions of LILO)
>2) booting and partitioning software from other OSs
>   (e.g., DOS FDISK, OS/2 FDISK)
>
>Command (m for help): p
>
>Disk /dev/hda: 60.0 GB, 60011642880 bytes
>16 heads, 63 sectors/track, 116280 cylinders
>Units = cylinders of 1008 * 512 = 516096 bytes
>
>   Device Boot      Start         End      Blocks   Id  System
>/dev/hda1               1         130       65488+  83  Linux
>Partition 1 does not end on cylinder boundary.
>/dev/hda2             131       79717    40111848    5  Extended
>Partition 2 does not end on cylinder boundary.
>/dev/hda3   *       79718       95960     8186314+  a5  FreeBSD
>Partition 3 does not end on cylinder boundary.
>/dev/hda4           95964      116279    10239264    c  W95 FAT32 (LBA)
>Partition 4 does not end on cylinder boundary.
>/dev/hda5            2212       79717    39063024   83  Linux
>/dev/hda6             131        2211     1048792+  82  Linux swap / Solaris
>
>  
>

Technically, there is no "error" here.  The first message is completely
normal for large disks.  The "does not end on..." messages mean that the
disk was originally parititoned in "LBA" mode (which represents the disk
as having 255 heads, and about 1/4 as many cylinders), but for some
reason, Linux is seeing the disk in non-LBA mode.  (side note: I really
don't understand why BIOSs don't provide an option that says "Force the
damn disk to LBA!!!")

Again, nothing actually wrong with this, but if you were to delete and
recreate any partitions with fdisk, it would insist on creatin the
partitions on a cylinder boundary, meaning they start/end sectors would
*not* be the same.  So, if you see such messages, either be prepared to
delete the entire table and start over, or don't change anything with fdisk!

>cfdisk doesn't even start but stops with the following message:
>
>FATAL ERROR: Bad logical partition 6: enlarged logical partitions overlap
>Press any key to exit cfdisk
>
>  
>

Well, this is most likely because it is extremely rare to have logical
volumes out of order in the extended volume.  So the sanity checks in
cfdisk might be fairly simple, like making sure the start cylinder of
hda6 comes after the end cylinder of hda5.  Sounds like a bug in cfdisk
if you ask me....

I think the only way to really get rid of the error messages would be to
do a full backup, then blow everything away, and then restore it. 
Probably not worth the effort though...

-Richard

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Re: [gentoo-user] fdisk errors after repartitioning

[Robert G. Siebeck]

Hi Benno,

2005/7/15, Benno Schulenberg <benno.schulenberg@gmail.com>:
> 
> Hi Robert,
> 
> > /dev/hda5            2212       79717    39063024   83  Linux
> > /dev/hda6             131        2211     1048792+  82  Linux
> > swap / Solaris
> >
> >
> > cfdisk doesn't even start but stops with the following message:
> >
> > FATAL ERROR: Bad logical partition 6: enlarged logical partitions
> > overlap Press any key to exit cfdisk
> 
> Have you tried using parted on this disk?  I'm quite curious as to
> what it will say about these out-of-order partitions, and the
> unusual boundaries.  (Be careful though with executing other
> commands than print, as they act immediately.)

I tried parted, but it doesn't report any errors:

(parted) print                                                            
Disk geometry for /dev/hda: 0.000-57231.562 megabytes
Disk label type: msdos
Minor    Start       End     Type      Filesystem  Flags
1          0.031     63.984  primary   ext2        
2         63.984  39235.710  extended              
6         64.015   1088.226  logical   linux-swap  
5       1088.227  39235.710  logical   reiserfs    
3      39235.711  47230.158  primary               boot
4      47231.789  57231.070  primary   fat32       lba


> Benno

Robert.

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