[Novalug] LVM query
James Ewing Cottrell 3rd
JECottrell3 at Comcast.NET
Tue Jul 20 02:01:58 EDT 2010
The MBR (which is where the Partition Table is stored) eats one track
from the first Primary Partition IFF that partition starts at Cylinder
1. The same is true wil all Logical Partitions, so I always waste a
cylinder between them.
On 7/19/2010 9:08 PM, Brander Snaxe wrote:
> What is the first track problem you mention? Is this something to do with LVM alignment? I have read about this before when dealing with filesystem alignment with RAID5 stripes. Also it comes into play with LVM. And it always comes into play with SSD drives apparently.
> I assume that for plain LVM or for LVM+RAID (no striping) that the mis-alignment problem would be so negligible that worrying about is moot.
> Just curious.
> Also, for anybody using LVM with XFS, forget about it unless you have a battery backed controller. LVM ignores barrier/nobarrier options on top of software RAID (at least it did when I last tried about 6 months ago).
> --- On Mon, 7/19/10, James Ewing Cottrell 3rd<JECottrell3 at Comcast.NET> wrote:
> If you want mirror or a
> RAID, use MD and build LVM on top of that. I just had a disk go bad, so
> I am doing exactly that: LVM on top of two disks, mirrored together.
> All partitions are Primary, and I start P1 at Cylinder 2 to avoid the
> short first track problem.
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