[linux-lvm] Non 512 byte sectors

Stuart D Gathman stuart at bmsi.com
Fri Dec 14 18:52:39 UTC 2012

On 12/13/2012 10:23 AM, Phillip Susi expounded in part:
> Hash: SHA1
> Is it possible to get dm to report > 512 byte sector size?  If so, how?
blockdev --getss /dev/vg/lv  (or any other block device)

That is probably logical sector size, however.  The only way I know to 
get physical sector size is:

hdparm -I /dev/sda

which reports logical and physical sector size.  Some WD devices are 
known to lie about physical sector size, however.

If you always align stuff to 4096, there won't be a problem.  In fact, 
new technology tends to have much larger alignment requirements for 
optimum performance - say 128k, the size of an erase block, or 64k for a 
RAID chunk size.  So aligning everything to 1M should hold you for a while.

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