Re: [linux-lvm] disk striping

["Stuart D. Gathman" <stuart bmsi com>]

On Wed, 14 May 2008, Jorge Souto wrote:

> I use lvm in a mainframe environment, with small ECKD disks (maximum model
> 54, aprox. 45 GB). So to create a big volume a I need a lot of disks. I'm
> going to create one with 35 physical volumes. I have doubts about striping,
> particularly deciding the number of stripes in such case (35 PVs in one
> storage array rank -yeah, not good-), and the drawbacks in administration
> tasks ( growing and limitations adding pvs to a stripped volume).

Idea 1:
Make 4 PVs of 8 disks with raid1+0 (create 4 mirror pairs, then
stripe the 4 mirrors in each group).  Keep the additional 3 disks
as spares.

Idea 2:
Make 7 PVs of 5 disks with raid5 (4 disks with 1 parity).

In each case, 4 way striping accelerates read/write by 4.  Each case
is able to tolerate single disk failures. 

-- 
	      Stuart D. Gathman <stuart bmsi com>
    Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
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