JBOD Raid 0,1

[Nick D'Angelo]

Experts,

I am trying to make sure that I configure my 10 disks in a raid 0,1 fashion.

It was supposed to be pre-configured by HP, but I would like to confirm.

Any ideas would be greatly appreciated.

[G. Vrijhoeven]

Hi,

software raid:

lvdisplay /dev/vg??/lvol??

Gideon

[A. Clay Stephenson]

Hi:

For each LVOL, do an lvdisplay -v /dev/vg0x/lvolx. The stripping patterns should be obvious as well as the existence of the mirror for each logical extent.

Clay

[Nick D'Angelo]

Yikes, nothing is striped.

How can I stripe them? I see that they are mirrored.

[A. Clay Stephenson · Accepted solution]

Hi Nick:

Here is a pretty good recipe:

SYS ADM: How to pseudo-stripe all copies of a mirrored lvol


Date : 2001 May 10
Description : SYS ADM: How to pseudo-stripe all copies of a mirrored lvol
Document Id : A4922912
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PROBLEM
I have a large Oracle database with approximately 100 disks in a 3-way
mirror, currently not manually striped. Each disk is either 4 GB or 2 GB,
with multiple 1 GB DB files. The disks are grouped in trays of threes,
three 2 GB or three 4 GB.

Can you assist me in striping and mirroring a large number of disks?

CONFIGURATION
Operating System - HP-UX
Version - 10.20
Hardware System - HP9000
Series - T500

RESOLUTION
Experimentation on the following example showed that pseudo-stripe
of a mirrored lvol (logical volume) when multiple disks are specified
on the lvextend command line indeed does stripe both the original and
the mirror. The example is from an S800 on 10.10.

1. vgdisplay -v /dev/vg00 | grep dsk

PV Name /dev/dsk/c0t5d0
PV Name /dev/dsk/c0t6d0
PV Name /dev/dsk/c0t1d0
PV Name /dev/dsk/c0t2d0

2. lvcreate -l 1 /dev/vg00 ---> lvol20

3. lvextend -m 1 /dev/vg00/lvol20 ; lvdisplay -v /dev/vg00/lvol20 --->
...
--- Logical extents ---
LE PV1 PE1 Status 1 PV2 PE2 Status 2
0000 /dev/dsk/c0t5d0 0441 current /dev/dsk/c0t6d0 0492 current

4. lvextend -l 2 /dev/vg00/lvol20 /dev/dsk/c0t1d0 /dev/dsk/c0t2d0

5. lvdisplay -v /dev/vg00/lvol20 --->

--- Logical extents ---
LE PV1 PE1 Status 1 PV2 PE2 Status 2
0000 /dev/dsk/c0t5d0 0441 current /dev/dsk/c0t6d0 0492 current
0001 /dev/dsk/c0t1d0 0068 current /dev/dsk/c0t2d0 0500 current

So, if you want to pseudo-stripe and mirror, and want both mirrors to
be pseudo-striped, then use these steps:

1. lvcreate -l 1 ---> to disk_1

2. lvextend -m 1 ---> to disk_2

3. lvextend -l 2 disk_3 disk_4 ---> now pseudo-stripe to disks 1 & 3,
with mirror on 2 & 4

4. lvextend -l 3 disk_1 disk_2 ; lvextend -l 4 disk_3 disk_4

and so forth.

In your situation with a 2-way mirror, striping across three disks,
you need nine disks total, and the lvextend should have
"disk_n disk_n+1 disk_n+2"; otherwise, it is identical to the
above example.

[G. Vrijhoeven]

Hi again.

take a look at this URL:

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90742/B2355-90742_top.html&con=/hpux/onlinedocs/B2355-90742/00/00/48-con.html&toc=/hpux/onlinedocs/B2355-90742/00/00/48-toc.html&searchterms=lvm%20stripe&queryid=20011010-061305
hope this wilL help.

Gideon

[Nick D'Angelo]

A. Clay,

Thanks, that looks like the ticket. I will attempt to complete this tomorrow.

Thanks to all.

Nickd