Rich Freeman on 8 Nov 2012 08:11:42 -0800


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Re: [PLUG] Partitioning big disks


On Thu, Nov 8, 2012 at 10:52 AM, Conor Schaefer
<conor.schaefer@gmail.com> wrote:
>> Notes for Linux users. Lots of info on web on how to handle the 4K
>> sectors, but no real straightforward "How To." Well here it is:
>>
>> Run fdisk with the -u parameter to partition the drive and select 64 as
>> the starting block (instead of default 63). Then, use the -b parameter in
>> mkfs to specify 4096 block sizes: mkfs -t ext3 -b 4096 /dev/sda1
>
>
> Have not tested this myself. Hope it's a nudge in the right direction....

I just got some new 4K drives and I found that fdisk actually was
defaulting to what seemed to be appropriate sector numbers.  I was
anticipating a nightmare since I have mdadm+LVM running on top of
those partitions, and so many opportunities to break alignment (plus
drives from different manufacturers, different sector sizes, reshaping
an existing array, etc).

I think I have it working, but short of redoing the whole thing 5 ways
and comparing benchmarks it is hard to say.  If somebody has guidance
on what the benchmarks should be like for ext4+lvm+mdadm on raid5 on
7200RPM disks, by all means let me know.

I'm really looking forward to when I can just run btrfs on bare metal...

Rich
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