I have just added a second WD 1Tb disk to my desktop system for backups and such.
It *looks* like the one that the system started with but it has some subtle differences and I wonder whether these are significant in any way.
Firstly fdisk reports slightly different geometry:-
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 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: 0xf24a2de7
Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 81 heads, 63 sectors/track, 382818 cylinders Units = cylinders of 5103 * 512 = 2612736 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x4e451e03
Secondly (and the one I have *slightly* more concern about) blkid reports as follows:-
/dev/sdc1: UUID="c4ae6fbe-18b3-4af9-aed8-a442e0fb6893" SEC_TYPE="ext2" TYPE="ext3" /dev/sdb1: UUID="6976542f-0471-411e-8c0d-97492c3f49b5" TYPE="ext3"
What does that SEC_TYPE="ext2" mean? I used mkfs.ext3 to create the file system on the disk with no explicit option. Presumably the other disk (/dev/sdb1) was partitioned and formatted when I installed xubuntu.
On 4 November 2010 16:46, Chris G cl@isbd.net wrote:
I have just added a second WD 1Tb disk to my desktop system for backups and such. Firstly fdisk reports slightly different geometry:-
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 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: 0xf24a2de7
Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 81 heads, 63 sectors/track, 382818 cylinders Units = cylinders of 5103 * 512 = 2612736 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x4e451e03
Is there a jumper for XP compatibility mode? My WD 1Tb is like your first one with 255 heads, and the jumper is not set.
Tim.
On Thu, Nov 04, 2010 at 04:52:11PM +0000, Tim Green wrote:
On 4 November 2010 16:46, Chris G cl@isbd.net wrote:
I have just added a second WD 1Tb disk to my desktop system for backups and such. Firstly fdisk reports slightly different geometry:-
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 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: 0xf24a2de7
Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 81 heads, 63 sectors/track, 382818 cylinders Units = cylinders of 5103 * 512 = 2612736 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x4e451e03
Is there a jumper for XP compatibility mode? My WD 1Tb is like your first one with 255 heads, and the jumper is not set.
Yes, there is something about XP compatibility, I did what it said for 'other' operating systems, i.e. nothing. I don't know how the jumpers on the earlier disk are set, I doubt I've changed them either but I'm not sure, I built the system quite a while ago.
On 04/11/10 17:58, Chris G wrote:
On Thu, Nov 04, 2010 at 04:52:11PM +0000, Tim Green wrote:
Is there a jumper for XP compatibility mode? My WD 1Tb is like your first one with 255 heads, and the jumper is not set.
Yes, there is something about XP compatibility, I did what it said for 'other' operating systems, i.e. nothing. I don't know how the jumpers on the earlier disk are set, I doubt I've changed them either but I'm not sure, I built the system quite a while ago.
That sounds like it is to do with the new 4KB sector size and the fact that you have the jumper unset and your OS is still telling you that you have 512 byte sectors is maybe a worry as that might...I am not sure indicate that you have a kernel that is too old to understand 4KB sectors.
Or maybe WD have emulated 512byte sectors on top of the new 4KB sectors and the jumper just controls the offset. I'd read up if I were you :)
Don't set the jumper back now as I have a nasty feeling that will scramble the contents of your drive. But if you are running a kernel that doesn't understand 4KB sectors on a drive that is set to that mode then you get miss-alignment in the sector map which will be costing you a bit of performance.
As to the reported geometry differences, I wouldn't worry too much, particularly if the drives aren't the exact same model. Cylinder, Head Sector addressing is pretty meaningless (and emulated) nowadays. What kernel versions are you both on ?
On Fri, Nov 05, 2010 at 12:03:30AM +0000, Wayne Stallwood wrote:
On 04/11/10 17:58, Chris G wrote:
On Thu, Nov 04, 2010 at 04:52:11PM +0000, Tim Green wrote:
Is there a jumper for XP compatibility mode? My WD 1Tb is like your first one with 255 heads, and the jumper is not set.
Yes, there is something about XP compatibility, I did what it said for 'other' operating systems, i.e. nothing. I don't know how the jumpers on the earlier disk are set, I doubt I've changed them either but I'm not sure, I built the system quite a while ago.
That sounds like it is to do with the new 4KB sector size and the fact that you have the jumper unset and your OS is still telling you that you have 512 byte sectors is maybe a worry as that might...I am not sure indicate that you have a kernel that is too old to understand 4KB sectors.
Or maybe WD have emulated 512byte sectors on top of the new 4KB sectors and the jumper just controls the offset. I'd read up if I were you :)
Don't set the jumper back now as I have a nasty feeling that will scramble the contents of your drive. But if you are running a kernel
I'm quite sure it would!
that doesn't understand 4KB sectors on a drive that is set to that mode then you get miss-alignment in the sector map which will be costing you a bit of performance.
I'm running a pretty recent kernel - 2.6.32-25-generic.
As to the reported geometry differences, I wouldn't worry too much, particularly if the drives aren't the exact same model. Cylinder, Head Sector addressing is pretty meaningless (and emulated) nowadays. What kernel versions are you both on ?
'both'? The original Ubuntu installation (which formatted the first drive) will be a few versions back from the current 2.6.32-25-generic.
On 5 November 2010 11:05, Chris G cl@isbd.net wrote:
On Fri, Nov 05, 2010 at 12:03:30AM +0000, Wayne Stallwood wrote: I'm running a pretty recent kernel - 2.6.32-25-generic.
As to the reported geometry differences, I wouldn't worry too much, particularly if the drives aren't the exact same model. Cylinder, Head Sector addressing is pretty meaningless (and emulated) nowadays. What kernel versions are you both on ?
'both'? The original Ubuntu installation (which formatted the first drive) will be a few versions back from the current 2.6.32-25-generic.
Both as in you and me?
Linux quicklime 2.6.32-25-generic #45-Ubuntu SMP Sat Oct 16 19:48:22 UTC 2010 i686 GNU/Linux Ubuntu 10.04.1 LTS
Tim.
On Fri, Nov 05, 2010 at 11:50:43AM +0000, Tim Green wrote:
On 5 November 2010 11:05, Chris G cl@isbd.net wrote:
On Fri, Nov 05, 2010 at 12:03:30AM +0000, Wayne Stallwood wrote: I'm running a pretty recent kernel - 2.6.32-25-generic.
As to the reported geometry differences, I wouldn't worry too much, particularly if the drives aren't the exact same model. Cylinder, Head Sector addressing is pretty meaningless (and emulated) nowadays. What kernel versions are you both on ?
'both'? The original Ubuntu installation (which formatted the first drive) will be a few versions back from the current 2.6.32-25-generic.
Both as in you and me?
Linux quicklime 2.6.32-25-generic #45-Ubuntu SMP Sat Oct 16 19:48:22 UTC 2010 i686 GNU/Linux Ubuntu 10.04.1 LTS
Exactly what I have too.
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Chris G -
Tim Green -
Wayne Stallwood