On Mon, Jan 17, 2011 at 3:42 AM, wrote:

On 2011. 01. 17., Monday 05:43:29 Andrew Joakimsen wrote:

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I've installed a new RAID array in my home server and the disks are using 4KB sectors instead of the traditional 512 byte sectors.

How do I properly align the partitions to this disk? YaST partitioner shows "cylinders" and I can not come up with a formula to convert cylinders to sectors. My understanding is since 8 x 512 = 4096 (4kb) all I need to do is ensure that my partitions are aligned to multiples of 8 sectors.

Unfortunately, it is not that trivial as aligning partition boundaries to multiples of 8. See this article (and comments): http://lwn.net/Articles/377895/

That article is concerned with 4KB physical sector drives with 4KB logical sector addressing. That is highly uncommon. Most drives of concern have 4KB physical and 512 byte logical sectors. For them, alignment is the only issue. hdparm can show you your logical / physical sector size and I think both are in /sys/block/sda/queue/*. You can use a liveCD to look at that I assume prior to installing. Greg -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

On Mon, Jan 17, 2011 at 10:25 AM, wrote:

On 2011. 01. 17., Monday 15:15:13 Greg Freemyer wrote:

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On Mon, Jan 17, 2011 at 3:42 AM,   wrote:

...

On 2011. 01. 17., Monday 05:43:29 Andrew Joakimsen wrote:

...

I've installed a new RAID array in my home server and the disks are using 4KB sectors instead of the traditional 512 byte sectors.

How do I properly align the partitions to this disk? YaST partitioner shows "cylinders" and I can not come up with a formula to convert cylinders to sectors. My understanding is since 8 x 512 = 4096 (4kb) all I need to do is ensure that my partitions are aligned to multiples of 8 sectors.

Unfortunately, it is not that trivial as aligning partition boundaries to multiples of 8. See this article (and comments): http://lwn.net/Articles/377895/

That article is concerned with 4KB physical sector drives with 4KB logical sector addressing.  That is highly uncommon.

Please check again. A quote: "One simply cannot run XP on a device which has been properly partitioned for 4K physical sector sizes. To cope with that, drive manufacturers have introduced an even worse hack: shifting all 512-byte logical sectors forward by one, so that logical sector 64 lands at the beginning of a physical sector. So any partitioning tool which wants to lay things out properly must know where the origin of the device actually is - and not all devices are entirely forthcoming with that information. "

This is the main reason I referred the original poster to the article: 512-byte logical sectors may be shifted by one.

You're right, I didn't read it closely. And I had forgotten about the offset problem. That concept basically fell by the wayside a couple years ago and I don't think any new shipping drives have a offset. The key piece of the article is: === With luck, the off-by-one problem will go away before it becomes a big issue. As James Bottomley put it: "...fortunately very few of these have been seen in the wild and we're hopeful they can be shot before they breed." But that doesn't fix the problem with the alignment of partitions for use by XP. === Drives with the off-by-one issue are still very rare. And as the article you point out says, the issue of supporting disks as they are actually shipping is not Linux's, it's XPs. Basically I gather one is ill-advised to run XP from a drive with 4KB sectors. Greg -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

On Mon, Jan 17, 2011 at 09:07, Greg Freemyer wrote:

On Mon, Jan 17, 2011 at 9:06 AM, Greg Freemyer wrote:

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stripe, but not raid is supported yet I suspect.

but not all raid is supported yet I suspect.

The RAID reports it is 512kb sectors. (I think the same thing happens with the disk direct) None of this helps answer my questions or get the partitions setup correctly: 1) How can I show sectors (instead of cylinders) in Yast partitioner? OR 2) How can I convert cylinders to sectors? -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

On Thu, Feb 3, 2011 at 16:58, Greg Freemyer wrote:

Did you read my post that the Yast Partitioner with openSUSE 11.3 will do it automatically.

Yes but when I look in /sys/block/sdb/queue there is nothing different than any other disk. Therefore how is the partitioner determining to do it automatically? I don't think it is. And none of the responses are helping to setup a correct partion scheme in Yast. All I want to know is how to show sectors in yast or how to convert sectors to cylinders! -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org