[linux-lvm] lvcreate distributed extent option

[ZECHA,HOLGER (HP-Germany,ex1)]

Hello,

what do you mean with 
> How about striping with the strip size equal to that of a logical extent?

Can you give an example for the lvcreate command.

The reason to do this is to distribute the disk I/O accross all disks. the
logical extent 1 is on disk1, logical extent 2 on disk 2 and so on.
This means during read of logical extent 1, the heade of the second disk can
already be moved to prepare to read logical extent 2.

This allows us to do more I/O's per second

Holger


-----Original Message-----
From: James Hawtin [mailto:oolon at pzat.meep.org]
Sent: Samstag, 30. November 2002 14:40
To: linux-lvm at sistina.com
Cc: lvm-devel at sistina.com
Subject: Re: [linux-lvm] lvcreate distributed extent option




On Sat, 30 Nov 2002, ZECHA,HOLGER (HP-Germany,ex1) wrote:

>
> Hello,
>
> I want to create a logical volume of 40GB Size using a physical 9GB
disks,is
> there a way to create a logical volume in the way, that the first logical
> extend is on disk one, the second on disk two, ... the 7th on disk one and
> so on ?
>
> Meaning all logical extends are distributed accross all disks.
>
> In HP-UX lvdisplay wwill look like this:
>    --- Logical extents ---
>    LE    PV1                PE1   Status 1
>    00000 /dev/dsk/c16t0d0   00012 current
>    00001 /dev/dsk/c16t0d1   00012 current
>    00002 /dev/dsk/c17t0d2   00000 current
>    00003 /dev/dsk/c17t0d3   00000 current
>    00004 /dev/dsk/c16t0d4   00000 current
>    00005 /dev/dsk/c16t0d5   00000 current
>    00006 /dev/dsk/c17t0d6   00000 current
>    00007 /dev/dsk/c17t0d7   00000 current
>    00008 /dev/dsk/c16t1d0   00000 current
>    00009 /dev/dsk/c16t1d1   00000 current
>    00010 /dev/dsk/c17t1d2   00000 current
>    00011 /dev/dsk/c17t1d3   00000 current
>    00012 /dev/dsk/c16t1d4   00000 current
>
> Holger
>

How about striping with the strip size equal to that of a logical extent?

otherwise if you have quite alot of disk space on another drive you could
create your lv on that one then move the extents one at a time to the
destinations drives using pvmove.....

One does wonder why you want to do this!

James




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