Not prepared for 4096 byte sector hard drives?

nodata lsof at
Mon Feb 15 19:56:11 UTC 2010

On 15/02/10 18:04, Eric Sandeen wrote:
> nodata wrote:
>> On 15/02/10 01:20, Ric Wheeler wrote:
>>> On 02/14/2010 11:59 AM, Neal Becker wrote:
>>>> Any truth here?
>>>> Byte_Sector_Hard_Drives
>>> We have actually been working hard to take advantage of the information that
>>> these drives export
>> Is this the same information as shown by hdparm?
> I don't know for sure if hdparm shows it; I don't think so.  If you mean:
>         -g     Display the drive geometry (cylinders, heads, sectors),  the
>                size (in sectors) of the device, and the starting offset (in
>                sectors) of the device from the beginning of the drive.

Yes this. For an OCZ drive this information seems completely bogus.

> then no...
> this info is exported in sysfs for each block device:
> [root at host queue]# pwd
> /sys/block/sdb/queue
> [root at host queue]# ls
> discard_granularity  iostats             nomerges             rotational
> discard_max_bytes    logical_block_size  nr_requests          rq_affinity
> discard_zeroes_data  max_hw_sectors_kb   optimal_io_size      scheduler
> hw_sector_size       max_sectors_kb      physical_block_size
> iosched              minimum_io_size     read_ahead_kb

I will compare it with this. Thanks.

> Many of these values are relevant to that article.  Several of these values
> are also available via ioctl.  libblkid is a nice interface to get to the
> values.  fdisk&  parted make use of it, as do mkfs.ext4 and mkfs.xfs ... etc.
> Some (all?) of the values above are described in Documentation/ABI/testing/sysfs-block
> in the kernel tree (or kernel-doc rpm)
> -Eric

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