[linux-lvm] lvcreate distributed extent option
Heinz J . Mauelshagen
mauelshagen at sistina.com
Tue Dec 3 05:19:02 UTC 2002
On Sat, Nov 30, 2002 at 10:24:06AM -0500, toby wrote:
> "ZECHA,HOLGER (HP-Germany,ex1)" wrote:
> > 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
> Once you create a striped lv, you cannot extend it by adding more disks. Current
> lvm version anyway.
That constraint doesn't exits any longer in LVM2/device-mapper
using the new LVM2 ondisk metadata format.
> I wanted mine to be more flexible, so I first made a software raid set then made
> the pv on top of the raid. That was in Jan this year. Last week I doubled the
> size by adding another software raid set. I expanded two of the ext3 formatted
> lvs in the process.
> Perhaps not the fastest system in terms of throughput, but quite convenient to
> linux-lvm mailing list
> linux-lvm at sistina.com
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
Heinz -- The LVM Guy --
*** Software bugs are stupid.
Nevertheless it needs not so stupid people to solve them ***
Heinz Mauelshagen Sistina Software Inc.
Senior Consultant/Developer Am Sonnenhang 11
Mauelshagen at Sistina.com +49 2626 141200
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