Check what /proc/partitions shows us. #blocks, with units of 1kB.
This has been standard in the kernel for a loooong time.
> The point is that if blk_size counts in KB, then the size of a device
> cannot reach more that 2^32 * 2^10 = 2^42 = 4TB. I'd personally say
> 2TB, becuase the int blk_size number is signed.
>
> That's rumoured not to be the case, and the max size of a device is
> supposed to be about 8 to 16TB. Let's suppose the rumour is true ..
Well, the rumor is wrong. There has always been a single-device 1TB/2TB
limit in the kernel (2^31 or 2^32 * 512 byte sector size), and until
recently it has not been a problem. To remove the problem Jens Axboe
(I think, or Ben LaHaise, can't remember) has a patch to support 64-bit
block counts and has been tested with > 2TB devices.
> So we deduce that one has to assign a different meaning for the blk_size
> array. "count in blocks" is how the rumour goes. That way you can get
> 4 times higher sizes .. all the way to 8 or 16TB per device. And this
> is what is rumoured to be the case.
Where do you get these rumors?
> It should be in blocks if the size of a device is to reach 8 or 16TB.
> If it is in KB, we are limited to 2 or 4TB.
In theory this is possible (it was discussed on the LVM list a bit), but
it would take a bunch of work to make it real. For LVM (and MD RAID),
since we are dealing with multiple real devices < 2TB in size, we could
use a blocksize of 4kB to get a larger virtual device. In the end this
only wins for a short time and you need 64-bit block numbers anyways.
> Persuade me that this is not a bug, and an important one at that :-)
> Hellloooooo everybody! Linux cannot manage partitions greater than
> 4TB, ha ha ha hhhhhaaaa! ;-)
And it can't handle more than 64GB of RAM on ia32 (was previously 1GB).
So what? When a limit is reached for any reasonable number of people,
it is fixed.
> I at least am getting up to devicesizes at the 8TB range.
If you are in that ballpark, then get the 64-bit blocknumber patch, and
start testing/fixing, instead of complaining.
Cheers, Andreas
-- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/