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SubjectRe: [ANNOUNCE] util-linux-ng v2.17 (stable)
On 2010-01-08, at 14:43, H. Peter Anvin wrote:
> On 01/08/2010 01:33 AM, Karel Zak wrote:
>> fdisk:
>> - the fdisk command aligns newly created partitions to
>> minimum_io_size
>> boundary ("minimum_io_size" is physical sector size or stripe
>> chunk
>> size on RAIDs).
>>
>> - the fdisk command supports disks with alignment_offset now.
>
> I think we should align, by default, much more aggressively than
> that --
> because frequently we just don't know what the real physical alignment
> is (think of flash media, which uses large erase blocks underneath.)
> Windows aligns partitions 1 MB boundaries by default now -- I think
> that's probably a reasonably good idea, at least for any disk that's
> not
> tiny, say 256 MB or less.

I agree whole heartedly. We steer users very sharply away from using
partitions at all, because on h/w RAID devices the 512-byte offset
from fdisk completely kills RAID-5/6 performance.

Making the default minimum alignment for DOS/GPT partitions makes a
lot of sense, and LVM PEs should be on 1MB boundaries as well (I don't
think that is the case today either).


Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.



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