Hello,

I have recently acquired a WD 2.5 Tb hard disk to replace a smaller one that was dying. As the disk has 4096 byte sectors instead of 512 I had some difficulties to get it partitioned and formatted, but it is working now. The partition scheme is:

1. Physical partition 100 Mb. /boot
2. Physical partition 250 Gb. / (ubuntu 10.04)
3. Physical partition 250 Gb. (kubuntu 11.10)
4. Extended
5. 3 Gb swap
6. 250 Gb.
...

The problem is that if I install linux on an extended partition, I cannot launch it. Grub does not seem to recognize the extended partitions.

grub rescue> ls
(hd0) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1)

Any hints?

Does bios support such a drive? Might have to set the chs limit jumper if you can't get it to work.

What does bios report for the drive?

Thank you for your reply.

I do not know if the bios support such a drive, the PC has already several years and HD with 4096 byte sectors are relatively recent. The bios reports:

WDC WD25E2RS-00J99B0
Capacity 2500 GB
Cylinder 65535
Head 16
Precomp 0
Landing zone 65534
Sector 255

#fdisk -l

Disk /dev/sda: 2500.5 GB, 2500495958016 bytes
255 heads, 63 sectors/track, 304001 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000d3911

Bios info seems wrong but anyway there is not much that one can set or change.
Anyway the bios recognizes the physical partitions, the problem is with the extended ones.


parted reports:

Model: ATA WDC WD25EZRS-00J (scsi)
Disk /dev/sda: 4883781168s
Sector size (logical/physical): 512B/4096B
Partition Table: msdos

Number Start End Size Type File system Flags
1 4096s 307199s 303104s primary ext3 boot
2 307200s 524287999s 523980800s primary ext4
3 524288000s 1048575999s 524288000s primary ext4
4 1048576000s 4883776064s 3835200065s extended lba
5 1048580096s 1054867455s 6287360s logical linux-swap(v1)
6 1054871552s 1579159551s 524288000s logical ext4
7 1579163648s 2103451647s 524288000s logical ext4
8 2103455744s 2627743743s 524288000s logical ext4
9 2627747840s 3676323839s 1048576000s logical ext4
10 3676327936s 4883776064s 1207448129s logical ext4

Hi

I had a similar problem before. Linux can have problems with disks over 2TB.

I can't remember the details, but I think I had to use parted/gparted. Something like this:

http://linuxhowtos.wikidot.com/using...eater-than-2tb

Thank you for your reply.

As it is described in the link the problem seems to be with partitions greater than 2TB, and the biggest partitions of the 2.5 TB hard disk are 500 GB so this should not be a problem. In practice it is the case: the second partition where Ubuntu resides can perfectly use the partitions 9 and 10 which contain data. The problem is just at boot time, Grub seems to not recognize extended partitions; once linux is loaded (2.6.32-38 kernel) extended partitions are recognized normally.

http://ubuntuforums.org/showthread.php?p=11282220

The last link has a way to work around unless you want to test all the stuff you have.

Of course you'll have to reformat the disk to gpt first - and lose all your data - I would recommend this though.
I wonder what the chaining looks like for logical partitions with 4k sectors ...